Christopher N Willmer

Interests

Research

Extragalactic Astrophysics, Evolution of Galaxies

Courses

Scholarly Contributions

Chapters

• Chincarini, G., Costa, L. N., Fairall, A. P., Pellegrini, P. S., Vettolani, G., & Willmer, C. N. (1988). Hydra — Centaurus: A Redshift Survey. In Large Scale Structures of the Universe: Proceedings of the 130th Symposium of the International Astronomical Union, dedicated to the memory of Marc A. Aaronson (1950-1987)(pp 522-523). Balatonfured, Hungary: Springer Netherlands. doi:10.1007/978-94-009-2995-1_78
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  The survey consists of 2 samples : SAMPLE A, 85% complete to B(T) = 14.0 in the region between 10 and 14 Hours in R.A. and between −20 and −50 degrees in DEC., SAMPLE B, complete to B(0) = 14.5 in two regions one between R.A. 13 and 14 hours, DEC between −25 and −33, the other between 11 and 12 hours, DEC from −33 to −27.

Journals/Publications

• Adams, N. J., Ferrami, G., Westcott, L., Harvey, T., Estrada-Carpenter, V., Conselice, C. J., Austin, D., Wyithe, J. S., Goolsby, C. M., Li, Q., Rusakov, V., Windhorst, R. A., Cohen, S. H., Jansen, R. A., Summers, J., O’Brien, R., Koekemoer, A. M., Driver, S. P., Frye, B., , Hathi, N. P., et al. (2025). JWSTs PEARLS: NIRCam imaging and NIRISS spectroscopy of a z = 3.6 star-forming galaxy lensed into a near-Einstein ring by a z = 1.258 massive elliptical galaxy. Monthly Notices of the Royal Astronomical Society, 543(Issue 4). doi:10.1093/mnras/staf1518
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  We present the discovery, and initial lensing analysis, of a high-redshift galaxy–galaxy lensing system within the JWSTPEARLS/HST–TREASUREHUNT North Ecliptic Pole Time Domain Field (designated NEPJ172238.9+655143.1). The lensing geometry shears a z = 3.6 ± 0.1 star-forming galaxy into a near-Einstein ring with a radius of 0.92 arcsec, consisting of 4 images, around a foreground massive elliptical galaxy at z = 1.258 ± 0.005. The system isfortuitously located within the NIRISS F200W footprint of the PEARLS survey, enabling spectroscopic identification of the 8500 Å TiO band in the foreground galaxy and allowing tight constraints to be placed on the redshift of the background galaxy based on its continuum detection and lack of strong emission lines. We calculate magnification factors of 2.6 < μ < 8.4 for the four images and a total lensing mass of (4.08 ± 0.07) × 1011 M. SED fitting of the foreground elliptical galaxy within the Einstein radius reveals a stellar mass of 1.26 × 1011 M under a Kroupa IMF, providing 31 per cent of the estimated lensing mass. Employing simple scaling relations and assumptions, an NFW dark matter halo is found to provide the correct remaining mass within 0.12+0.21−0.09 dex. However, if a modified IMF for elliptical galaxies is employed (e.g. bottom-heavy or bottom-and-top-heavy), stellar mass estimations increase and can account for the majority of the lensing mass, reducing the need for dark matter. This system further demonstrates the new discovery space that the combined wavelength coverage, sensitivity and resolution of James Webb Space Telescope (JWST) now enables.
• Bonaventura, N., Lyu, J., Rieke, G. H., Alberts, S., Willmer, C. N., Pérez-González, P. G., Bunker, A. J., Stone, M., D’Eugenio, F., Williams, C. C., Maseda, M. V., Willott, C. J., Ji, Z., Baker, W. M., Carniani, S., Charlot, S., Chevallard, J., Curtis-Lake, E., Eisenstein, D. J., , Hainline, K., et al. (2025). The Relation between AGN and Host-galaxy Properties in the JWST Era. I. Seyferts at Cosmic Noon are Obscured and Disturbed. Astrophysical Journal, 978(Issue 1). doi:10.3847/1538-4357/ad95ec
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  The morphology of a galaxy reflects the mix of physical processes occurring within and around it, offering indirect clues to its formation and evolution. We apply both visual classification and computer vision to test the suspected connection between galaxy mergers and active galactic nucleus (AGN) activity, as evidenced by a close/merging galaxy pair, or tidal features surrounding an apparently singular system. We use JADES JWST/NIRCam imagery of a complete, multiwavelength AGN sample recently expanded with JWST/Mid-Infrared Instrument (MIRI) photometry. This 0.9-25 μm data set enables constraints on the host-galaxy morphologies of a broad range of AGN beyond z ∼ 1, including heavily obscured examples missing from previous studies. Our primary AGN sample consists of 243 lightly to highly obscured X-ray-selected AGN and 138 presumed Compton-thick, mid-infrared-bright/X-ray-faint AGN revealed by MIRI. Utilizing the shape asymmetry morphology indicator, AS, as the metric for disturbance, we find that 88% of the Seyferts sampled are strongly spatially disturbed (AS > 0.2). The experimental design we employ reveals a ≳3σ obscuration-merger (NH-AS) correlation at 0.6 < z < 2.4, and also recovers a physical distinction between the X-ray- and mid-IR-detected AGN suggestive of their link to a common evolutionary scenario. Placing the observed pattern of disturbances in the context of the other average host-galaxy properties, we conclude that mergers are common among obscured AGN. This finding presents tension with the leading model on AGN fueling that requires Seyfert AGN with subquasar luminosities (Lbol < 1045 erg s−1) to evolve only through nonmerger mechanisms.
• Carniani, S., D'Eugenio, F., Ji, X., Parlanti, E., Scholtz, J., Sun, F., Venturi, G., Bakx, T. J., Curti, M., Maiolino, R., Tacchella, S., Zavala, J. A., Hainline, K., Witstok, J., Johnson, B. D., Alberts, S., Bunker, A. J., Charlot, S., Eisenstein, D. J., , Helton, J. M., et al. (2025). The eventful life of a luminous galaxy at z = 14: Metal enrichment, feedback, and low gas fraction?. Astronomy and Astrophysics, 696. doi:10.1051/0004-6361/202452451
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  JADES-GS-z14-0 is the most distant spectroscopically confirmed galaxy yet, at z & 14. With a UV magnitude of -20.81, it is one of the most luminous galaxies at cosmic dawn and its half-light radius of 260 pc means that stars dominate the observed UV emission. We report the Atacama Large Millimeter/submillimeter Array (ALMA) detection of [O iii]88 μm line emission with a significance of 6.67σ and at a frequency of 223.524 GHz, corresponding to a redshift of 14:1796±0:0007, which is consistent with the candidate Ciii] line detected in the NIRSpec spectrum. At this spectroscopic redshift, the Lyman-α break identified with NIRSpec requires a damped Lyman-α absorber with a column density of log(NHI=cm-2) = 21:96. The total [O iii]88 μm luminosity (log(L[OIII]=L⊙) = 8:3 ± 0:1) is fully consistent with the local L[OIII] - S FR relation and indicating a gas-phase metallicity >0:1 Z⊙. Using prospector spectral energy distribution (SED) modeling and combining the ALMA data with JWST observations, we find Z = 0:17 Z⊙ and a nonzero escape fraction of ionizing photons (∼11%), which is necessary by the code to reproduce the UV spectrum. We measure an [OIII]5007A=[OIII]88 μm line flux ratio between 1 and 20, resulting in an upper limit to the electron density of roughly 700 cm-3 assuming a single-cloud photoionization model. The [O iii]emission line is spectrally resolved, with a FWHM of 102+29 -22 km s-1, resulting in a dynamical mass of log(Mdyn=M⊙) = 9:0 ± 0:2. When compared to the stellar mass, this value represents a conservative upper limit on the gas mass fraction, which ranges from 50% to 80%, depending on the assumed star formation history. Past radiationdriven outflows may have cleared the galaxy from the gas, reducing the gas fraction and thus increasing the escape fraction of ionizing photons.
• Carranza-Escudero, M., Conselice, C. J., Adams, N., Harvey, T., Austin, D., Behroozi, P., Ferreira, L., Ormerod, K., Duan, Q., Trussler, J., Li, Q., Westcott, L., Windhorst, R. A., Coe, D., Cohen, S. H., Cheng, C., Driver, S. P., Frye, B., Furtak, L. J., , Grogin, N. A., et al. (2025). Lonely Little Red Dots: Challenges to the Active Galactic Nucleus Nature of Little Red Dots through Their Clustering and Spectral Energy Distributions. Astrophysical Journal Letters, 989(Issue 2). doi:10.3847/2041-8213/adf73d
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  Observations with the James Webb Space Telescope reveal a previously unseen population of compact red objects, known as “little red dots” (LRDs). We study a new photometrically selected sample of 124 LRDs in the redshift range z ∼ 3-10 selected from Near Infrared Camera coverage of the Cosmic Evolution Early Release Science Survey (CEERS), North Ecliptic Pole Time Domain Field (NEP-TDF), James Webb Space Telescope Advanced Deep Extragalactic Survey (JADES), and JEMS. For JADES, the NEP-TDF, and CEERS, we compare spectral energy distribution (SED) models with and without active galactic nucleus (AGN) components and analyze the impact of an AGN component on the goodness of fit using the Bayesian information criterion (BIC). We find that while the χ2 of the majority of models containing AGN components is improved compared to models without AGN components, we show that the BIC suggests that models without AGN are a more appropriate fit to LRD SEDs, especially when MIRI data are available. We also measure LRD clustering in the CEERS field, JADES field, and NEP-TDF, where we compare the spatial distribution of LRDs and galaxies with Kolmogorov-Smirnov tests of equality of distribution. We find that the neighbourhood of LRDs tends to be less dense compared to galaxies at all selections and masses and at similar redshifts. We further measure upper limit estimates for the halo masses of LRDs using abundance matching. While the population of LRDs could be a mixture of several different inherent populations, as a whole, it does appear that these systems are mostly hosting compact galaxies or star clusters in formation.
• Conselice, C. J., Adams, N., Harvey, T., Austin, D., Ferreira, L., Ormerod, K., Duan, Q., Trussler, J., Li, Q., Juodžbalis, I., Westcott, L., Harris, H., Seeyave, L. T., Bluck, A. F., Windhorst, R. A., Bhatawdekar, R., Coe, D., Cohen, S. H., Cheng, C., , Driver, S. P., et al. (2025). EPOCHS. I. The Discovery and Star-forming Properties of Galaxies in the Epoch of Reionization at 6.5 < z < 18 with PEARLS and Public JWST Data. Astrophysical Journal, 983(Issue 1). doi:10.3847/1538-4357/ada608
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  We present in this paper the discovery, properties, and a catalog of 1165 high-redshift 6.5 < z < 18 galaxies found in deep JWST NIRCam imaging from the GTO PEARLS survey combined with data from JWST public fields. We describe our bespoke homogeneous reduction process and our analysis of these areas including the NEP, CEERS, GLASS, NGDEEP, JADES, and ERO SMACS-0723 fields with over 214 arcmin2 imaged to depths of ∼30 mag. We describe our rigorous methods for identifying these galaxies, involving the use of Lyman-break strength, detection significance criteria, visual inspection, and integrated photometric redshift probability distributions predominately at high redshift. Our sample is a robust and highly pure collection of distant galaxies from which we also remove brown dwarf stars, and calculate completeness and contamination from simulations. We include a summary of the basic properties of these z > 6.5 galaxies, including their redshift distributions, UV absolute magnitudes, and star formation rates. Our study of these young galaxies reveals a wide range of stellar population properties as seen in their colors and SED fits, which we compare to stellar population models, indicating a range of star formation histories (SFHs), dust, active galactic nuceli, and/or nebular emission. We find that a strong trend exists between stellar mass and (U − V) color, as well as the existence of the “main-sequence” of star formation for galaxies as early as z ∼ 12. This indicates that stellar mass, or an underlying variable correlating with stellar mass, is driving galaxy formation, in agreement with simulation predictions. We also discover ultra-high-redshift candidates at z > 12 in our sample and describe their properties. Finally, we note a significant observed excess of galaxies compared to models at z > 12, revealing a tension between predictions and our observations.
• Curti, M., Witstok, J., Jakobsen, P., Kobayashi, C., Curtis-Lake, E., Hainline, K., Ji, X., D'Eugenio, F., Chevallard, J., Maiolino, R., Scholtz, J., Carniani, S., Arribas, S., Baker, W. M., Bhatawdekar, R., Boyett, K., Bunker, A. J., Cameron, A., Cargile, P. A., , Charlot, S., et al. (2025). JADES: The star formation and chemical enrichment history of a luminous galaxy at z ∼ 9.43 probed by ultra-deep JWST/NIRSpec spectroscopy. Astronomy and Astrophysics, 697. doi:10.1051/0004-6361/202451410
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  We analysed ultra-deep JWST observations of the galaxy JADES-GS-z9-0 at z = 9.4327, and derived detailed stellar and interstellar medium (ISM) properties of this luminous (MUV=-20.43) high-redshift system. Complementary information from NIRCam imaging and NIRSpec spectroscopy (both low and medium resolution) reveal a compact system (Re∼110 pc) characterised by a steeply rising star formation history, which is reflected in the inferred young stellar age (t∼3 Myr, light-weighted), high star formation rate surface density (ΣSFR∼72 M⊙ yr-1 kpc-2), high ionisation parameter (log(U) ∼-1.5), low metallicity (12 + log(O/H) ∼7.5), and low carbon-to-oxygen abundance ([C/O] =-0.64). Leveraging the detection of Na III] λ1750 we derived a nitrogen-to-oxygen abundance ([N/O] ∼0) higher than the plateau followed by low-redshift galaxies of similar metallicity, possibly revealing the imprint from (very) massive stars on the ISM enrichment and favouring a top-heavy initial mass function (IMF) scenario. Massive stars powering a hard radiation field are also required to explain the rest-frame UV line ratios, though the presence of the high-excitation [Ne V] λ3426 emission line possibly hints at additional ionisation from an active galactic nucleus (AGN). We also report the tentative detection of Lyα emission in the G140M spectrum, shifted by ∼450 km/s redwards of the systemic redshift. Combined with a modelling of the Lyα spectral break, we rule out the presence of very high column densities of neutral gas pertaining to local absorbers, as well as any extended surrounding ionised bubbles, suggesting that JADES-GS-z9-0 has not yet significantly contributed to cosmic reionisation.
• D'Eugenio, F., Helton, J. M., Hainline, K., Sun, F., Maiolino, R., Pérez-González, P. G., Juodžbalis, I., Arribas, S., Bunker, A. J., Carniani, S., Curtis-Lake, E., Egami, E., Eisenstein, D. J., Johnson, B. D., Robertson, B., Tacchella, S., Willmer, C. N., Willott, C., Baker, W. M., , Danhaive, A. L., et al. (2025). JADES and SAPPHIRES: Galaxy metamorphosis amidst a huge, luminous emission-line region. Monthly Notices of the Royal Astronomical Society, 542(Issue 2). doi:10.1093/mnras/staf1138
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  We report the discovery of a remarkably large and luminous line-emitting nebula extending on either side of the Balmer-break galaxy JADES-GS-518794 at, detected with James Webb Space Telescope (JWST)/NIRCam imaging in [O iii]4959, 5007 and H α and spectroscopically confirmed with NIRCam/wide-field slitless spectroscopy, thanks to the pure-parallel programme Slitless Areal Pure Parallel HIgh-Redshift Emission Survey. The end-to-end velocity offset is. Nebulae with such large sizes and high luminosities (25 pkpc diameter,) are routinely observed around bright quasars, unlike JADES-GS-518794. With a stellar mass of, this galaxy is at the knee of the mass function at. Its star formation rate declined for some time (10-100 Myr prior to observation), followed by a recent (10 Myr) upturn. This system is part of a candidate large-scale galaxy overdensity, with an excess of Balmer-break galaxies compared to the field (3σ). We discuss the possible origin of this nebula as material from a merger or gas expelled by an active galactic nucleus (AGN). The symmetry of the nebula, its bubble-like morphology, kinematics, high luminosity, and the extremely high equivalent width of [O iii] together favour the AGN interpretation. Intriguingly, there may be a physical connection between the presence of such a large, luminous nebula and the possible metamorphosis of the central galaxy towards quenching.
• DeCoursey, C., Egami, E., Pierel, J. D., Sun, F., Rest, A., Coulter, D. A., Engesser, M., Siebert, M. R., Hainline, K. N., Johnson, B. D., Bunker, A. J., Cargile, P. A., Charlot, S., Chen, W., Curti, M., DeFour-Remy, S., Eisenstein, D. J., Fox, O. D., Gezari, S., , Gomez, S., et al. (2025). The JADES Transient Survey: Discovery and Classification of Supernovae in the JADES Deep Field. Astrophysical Journal, 979(Issue 2). doi:10.3847/1538-4357/ad8fab
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  The JWST Advanced Deep Extragalactic Survey (JADES) is a multicycle JWST program that has taken among the deepest near- and mid-infrared images to date (down to ∼30 AB mag) over ∼25 arcmin2 in the GOODS-S field in two sets of observations with 1 yr of separation. This presented the first opportunity to systematically search for transients, mostly supernovae (SNe), out to z > 2. We found 79 SNe: 38 at z < 2, 23 at 2 < z < 3, 8 at 3 < z < 4, 7 at 4 < z < 5, and 3 with undetermined redshifts, where the redshifts are predominantly based on spectroscopic or highly reliable JADES photometric redshifts of the host galaxies. At this depth, the detection rate is ∼1-2 arcmin-2 yr-1, demonstrating the power of JWST as an SN discovery machine. We also conducted multiband follow-up NIRCam observations of a subset of the SNe to better constrain their light curves and classify their types. Here, we present the survey, sample, search parameters, spectral energy distributions, light curves, and classifications. Even at z ≥ 2, the NIRCam data quality is high enough to allow SN classification via multiepoch light-curve fitting with confidence. The multiepoch SN sample includes a Type Ia SN at z spec = 2.90, a Type IIP SN at z spec = 3.61, and a Type Ic-BL SN at z spec = 2.83. We also found that two z ∼ 16 galaxy candidates from the first imaging epoch were actually transients that faded in the second epoch, illustrating the possibility that moderate/high-redshift SNe could mimic high-redshift dropout galaxies.
• Duan, Q., Conselice, C. J., Li, Q., Austin, D., Harvey, T., Adams, N. J., Duncan, K. J., Trussler, J., Ferreira, L., Westcott, L., Harris, H., Windhorst, R. A., Holwerda, B. W., Broadhurst, T. J., Coe, D., Cohen, S. H., Du, X., Driver, S. P., Frye, B., , Grogin, N. A., et al. (2025). Galaxy mergers in the epoch of reionization - I. A JWST study of pair fractions, merger rates, and stellar mass accretion rates at z = 4.5-11.5. Monthly Notices of the Royal Astronomical Society, 540(Issue 1). doi:10.1093/mnras/staf638
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  We present a full analysis of galaxy major merger pair fractions, merger rates, and mass accretion rates, thus uncovering the role of mergers in galaxy formation at the earliest previously unexplored epoch of
• D’Eugenio, F., Cameron, A. J., Scholtz, J., Carniani, S., Willott, C. J., Curtis-Lake, E., Bunker, A. J., Parlanti, E., Maiolino, R., Willmer, C. N., Jakobsen, P., Robertson, B. E., Johnson, B. D., Tacchella, S., Cargile, P. A., Rawle, T., Arribas, S., Chevallard, J., Curti, M., , Egami, E., et al. (2025). JADES Data Release 3: NIRSpec/Microshutter Assembly Spectroscopy for 4000 Galaxies in the GOODS Fields. Astrophysical Journal, Supplement Series, 277(Issue 1). doi:10.3847/1538-4365/ada148
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  We present the third data release of the JWST Advanced Deep Extragalactic Survey (JADES), providing both imaging and spectroscopy in the two GOODS fields. Spectroscopy consists of medium-depth and deep NIRSpec/microshutter assembly spectra of 4000 targets, covering the spectral range 0.6-5.3 μm and observed with both the low-dispersion prism (R = 30-300) and all three medium-resolution gratings (R = 500-1500). We describe the observations, data reduction, sample selection, and target allocation. We measured 2375 redshifts (2053 from multiple emission lines); our targets span the range from z = 0.5 up to z = 13, including 404 at z > 5. The data release includes 2D and 1D fully reduced spectra, with slit-loss corrections and background subtraction optimized for point sources. We also provide redshifts and signal-to-noise ratio > 5 emission-line flux catalogs for the prism and grating spectra, and concise guidelines on how to use these data products. Alongside spectroscopy, we are also publishing fully calibrated NIRCam imaging, which enables studying the JADES sample with the combined power of imaging and spectroscopy. Together, these data provide the largest statistical sample to date to characterize the properties of galaxy populations in the first billion years after the Big Bang.
• D’Silva, J. C., Driver, S. P., Lagos, C. D., Robotham, A. S., Adams, N. J., Conselice, C. J., Frye, B., Hathi, N. P., Harvey, T., Koekemoer, A. M., Ortiz, R., Ricotti, M., Robertson, C., Rutkowski, M. J., Silver, R. M., Wilkins, S. M., Willmer, C. N., Windhorst, R. A., Cohen, S. H., , Jansen, R. A., et al. (2025). Self-consistent JWST Census of Star Formation and AGN Activity at z = 5.5-13.5. Astrophysical Journal, 990(Issue 1). doi:10.3847/1538-4357/adf19e
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  The cosmic star formation history (CSFH) and cosmic active galactic nuclei (AGN) luminosity history (CAGNH) are self consistently measured at z = 5.5-13.5. This is achieved by analyzing galaxies detected by the James Webb Space Telescope from ≈ 400 arcmin 2 fields from the Prime Extragalactic Areas of Reionization and Lensing Science, Cosmic Evolution Early Release Science, Next Generation Deep Extragalactic Exploratory Public, JWST Advanced Deep Extragalactic Survey, and Public Release IMaging for Extragalactic Research surveys. In particular, the combination of spectral energy distribution fitting codes, EAZY and ProSpect, is employed to estimate the photometric redshifts and astrophysical quantities of 3751 distant galaxies, from which we compute the stellar mass, star formation rate, and AGN luminosity distribution functions in four redshift bins. Integrating the distribution functions, we find that the CSFH rises by ≈1 dex over z = 13.5-5.5, and the CAGNH rises by ≈1 dex over z = 10.5-5.5. We connect our results of the CSFH and CAGNH at z = 13.5-5.5 to that from z = 5-0 to determine the summary of ≳13 Gyr of star formation and AGN activity, from the very onset of galaxy formation to the present day.
• Finkelstein, S. L., Bagley, M. B., Arrabal Haro, P., Dickinson, M., Ferguson, H. C., Kartaltepe, J. S., Kocevski, D. D., Koekemoer, A. M., Lotz, J. M., Papovich, C., Pérez-González, P. G., Pirzkal, N., Somerville, R. S., Trump, J. R., Yang, G., Yung, L. Y., Fontana, A., Grazian, A., Grogin, N. A., , Kewley, L. J., et al. (2025). The Cosmic Evolution Early Release Science Survey (CEERS). Astrophysical Journal Letters, 983(Issue 1). doi:10.3847/2041-8213/adbbd3
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  We present the Cosmic Evolution Early Release Science (CEERS) Survey, a 77.2 hr Director’s Discretionary Early Release Science Program. CEERS demonstrates, tests, and validates efficient extragalactic surveys using coordinated, overlapping parallel observations with the JWST instrument suite, including NIRCam and MIRI imaging, NIRSpec low- (R ∼ 100) and medium- (R ∼ 1000) resolution spectroscopy, and NIRCam slitless grism (R ∼ 1500) spectroscopy. CEERS targets the Hubble Space Telescope-observed region of the Extended Groth Strip field, supported by a rich set of multiwavelength data. CEERS facilitated immediate community science in both of the extragalactic core JWST science drivers “First Light” and “Galaxy Assembly,” including: (1) the discovery and characterization of large samples of galaxies at z ≳ 10 from ∼90 arcmin2 of NIRCam imaging, constraining their abundance and physical nature; (2) deep spectra of >1000 galaxies, including dozens of galaxies at 6 < z < 10, enabling redshift measurements and constraints on the physical conditions of star formation and black hole growth via line diagnostics; (3) quantifying the first bulge, bar, and disk structures at z > 3; and (4) characterizing galaxy mid-IR emission with MIRI to study dust-obscured star formation and supermassive black hole growth at z ∼ 1-3. As a legacy product for the community, the CEERS team has provided several data releases, accompanied by detailed notes on the data reduction procedures and notebooks to aid in reproducibility. In addition to an overview of the survey and the quality of the data, we provide science highlights from the first two years with CEERS data.
• Fu, S., Sun, F., Jiang, L., Lin, X., Diego, J. M., Furtak, L. J., Jauzac, M., Koekemoer, A. M., Li, M., Oguri, M., Patel, N. R., Willmer, C. N., Windhorst, R. A., Zitrin, A., Bauer, F. E., Chen, C. C., Chen, W., Cheng, C., Conselice, C. J., , Eisenstein, D. J., et al. (2025). Medium-band Astrophysics with the Grism of NIRCam In Frontier Fields (MAGNIF): Spectroscopic Census of Hα Luminosity Functions and Cosmic Star Formation at z ∼ 4.5 and 6.3. Astrophysical Journal, 987(Issue 2). doi:10.3847/1538-4357/adddb1
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  We measure Hα luminosity functions (LFs) at redshifts z ∼ 4.5 and 6.3 using the JWST Medium-band Astrophysics with the Grism of NIRCam In Frontier fields (MAGNIF) survey. MAGNIF obtained NIRCam grism spectra with the F360M and F480M filters in four Frontier Fields. We identify 248 Hα emitters based on the grism spectra and photometric redshifts from combined Hubble Space Telescope and JWST imaging data. The numbers of the Hα emitters show a large field-to-field variation, highlighting the necessity of multiple fields to mitigate cosmic variance. We calculate observed and dust-corrected Hα LFs at the two redshifts. Thanks to the gravitational lensing, the measured Hα LFs span three orders of magnitude in luminosity, and the faint-end luminosity reaches LHα ∼ 1040.3 erg s−1 at z ∼ 4.5 and 1041.5 erg s−1 at z ∼ 6.3. They correspond to star formation rates of ∼0.1 and 1.7 M⊙ yr−1, respectively. We conclude no or weak redshift evolution of the faint-end slope of Hα LF across z ≃ 0.4-6.3, and the comparison with the faint-end slopes of UV LF indicates stochastic star formation history among low-mass Hα emitters. The derived cosmic star formation rate densities are 0.05 8 − 0.006 + 0.008 M ⊙ yr − 1 Mpc − 3 at z ∼ 4.5 and 0.02 5 − 0.007 + 0.009 M ⊙ yr − 1 Mpc − 3 at z ∼ 6.3. These are approximately 2.2 times higher than previous estimates based on dust-corrected UV LFs, but consistent with recent measurements from infrared surveys. We discuss uncertainties in the Hα LF measurements, including those propagated from the lens models, cosmic variance, and active galactic nucleus contribution, and we find that they have a negligible impact on the above results.
• Hainline, K. N., Maiolino, R., Juodžbalis, I., Scholtz, J., Übler, H., D’Eugenio, F., Helton, J. M., Sun, Y., Sun, F., Robertson, B., Tacchella, S., Bunker, A. J., Carniani, S., Charlot, S., Curtis-Lake, E., Egami, E., Johnson, B. D., Lin, X., Lyu, J., , Pérez-González, P. G., et al. (2025). An Investigation into the Selection and Colors of Little Red Dots and Active Galactic Nuclei. Astrophysical Journal, 979(Issue 2). doi:10.3847/1538-4357/ad9920
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  Recently, a large number of compact sources at z > 4 with blue UV slopes and extremely red rest-frame optical slopes have been found in James Webb Space Telescope (JWST) extragalactic surveys. As a subsample of these sources, commonly called “little red dots” (LRDs), have been spectroscopically observed to host a broad-line active galactic nucleus (AGN), they have been the focus of multiple recent studies in an attempt to understand the origin of their UV and optical emission. Here, we assemble a sample of 123 LRDs from the literature along with spectroscopic and photometric JWST-identified samples of AGNs to compare their colors and spectral slopes. We find that while obscured AGNs at z < 6 have highly dissimilar colors to LRDs, unobscured AGNs at z < 6 span a wide range of colors, with only a subsample showing colors similar to LRDs. At z > 6, the majority of the unobscured AGNs that have been found in these samples are LRDs, but this may be related to the fact that these sources are at large bolometric luminosities. Because LRDs occupy a unique position in galaxy color space, they are more straightforward to target, and the large number of broad-line AGNs that do not have LRD colors and slopes are therefore underrepresented in many spectroscopic surveys because they are more difficult to preselect. Current LRD selection techniques return a large and disparate population, including many sources having 2-5 μm colors impacted by emission-line flux boosting in individual filters.
• Harvey, T., Conselice, C. J., Adams, N. J., Austin, D., Juodžbalis, I., Trussler, J., Li, Q., Ormerod, K., Ferreira, L., Lovell, C. C., Duan, Q., Westcott, L., Harris, H., Bhatawdekar, R., Coe, D., Cohen, S. H., Caruana, J., Cheng, C., Driver, S. P., , Frye, B., et al. (2025). EPOCHS. IV. SED Modeling Assumptions and Their Impact on the Stellar Mass Function at 6.5 ≤ z ≤ 13.5 Using PEARLS and Public JWST Observations. Astrophysical Journal, 978(Issue 1). doi:10.3847/1538-4357/ad8c29
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  We utilize deep JWST Near Infrared Camera (NIRCam) observations for the first direct constraints on the Galaxy Stellar Mass Function (GSMF) at z > 10. Our EPOCHS v1 sample includes 1120 galaxy candidates at 6.5 < z < 13.5 taken from a consistent reduction and analysis of publicly available deep JWST NIRCam data covering the Prime Extragalactic Areas for Reionization Science, CEERS, GLASS, JADES GOOD-S, NGDEEP, and SMACS0723 surveys, totaling 187 arcmin2. We investigate the impact of spectral energy distribution fitting methods, assumed star formation histories (SFHs), dust laws, and priors on galaxy masses and the resultant GSMF. While our fiducial GSMF agrees with the literature at z < 13.5, we find that the assumed SFH model has a large impact on the GSMF and stellar mass density (SMD), finding a 0.75 dex increase in the SMD at z = 10.5 between a flexible nonparametric and standard parametric SFH. Overall, we find a flatter SMD evolution at z ≥ 9 than some studies predict, suggesting a rapid buildup of stellar mass in the early Universe. We find no incompatibility between our results and those of standard cosmological models, as suggested previously, although the most massive galaxies may require a high star formation efficiency. We find that the “little red dot” galaxies dominate the z = 7 GSMF at high masses, necessitating a better understanding of the relative contributions of active galactic nucleus and stellar emission. We show that assuming a theoretically motivated top-heavy initial mass function (IMF) reduces stellar mass by 0.5 dex without affecting fit quality, but our results remain consistent with existing cosmological models with a standard IMF.
• Helton, J. M., Rieke, G. H., Alberts, S., Wu, Z., Eisenstein, D. J., Hainline, K. N., Carniani, S., Ji, Z., Baker, W. M., Bhatawdekar, R., Bunker, A. J., Cargile, P. A., Charlot, S., Chevallard, J., D’Eugenio, F., Egami, E., Johnson, B. D., Jones, G. C., Lyu, J., , Maiolino, R., et al. (2025). Photometric detection at 7.7 μm of a galaxy beyond redshift 14 with JWST/MIRI. Nature Astronomy, 9(Issue 5). doi:10.1038/s41550-025-02503-z
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  The James Webb Space Telescope (JWST) has spectroscopically confirmed numerous galaxies at z > 10. While weak rest-frame ultraviolet emission lines have only been seen in a handful of sources, the stronger rest-frame optical emission lines are highly diagnostic and accessible at mid-infrared wavelengths with the Mid-Infrared Instrument (MIRI) of JWST. We report the photometric detection of the distant spectroscopically confirmed galaxy JADES-GS-z14-0 at z=14.32−0.20+0.08 with MIRI at 7.7 μm. The most plausible solution for the stellar-population properties is that this galaxy contains half a billion solar masses in stars with a strong burst of star formation in the most recent few million years. For this model, at least one-third of the flux at 7.7 μm originates from the rest-frame optical emission lines Hβ and/or [O iii]λλ4959, 5007. The inferred properties of JADES-GS-z14-0 suggest rapid mass assembly and metal enrichment during the earliest phases of galaxy formation. This work demonstrates the unique power of mid-infrared observations in understanding galaxies at the redshift frontier.
• Ji, Z., Alberts, S., Zhu, Y., Vanzella, E., Giavalisco, M., Hainline, K., Baker, W. M., Bunker, A. J., Helton, J. M., Lyu, J., Rinaldi, P., Robertson, B., Simmonds, C., Tacchella, S., Williams, C. C., Willmer, C. N., & Witstok, J. (2025). The Importance of Dust Distribution in Ionizing-photon Escape: NIRCam and MIRI Imaging of a Lyman Continuum-emitting Galaxy at z ∼ 3.8. Astrophysical Journal Letters, 988(Issue 2). doi:10.3847/2041-8213/adf194
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  We present deep JWST/NIRCam and MIRI imaging of Ion1, a previously confirmed Lyman continuum (LyC)-emitting galaxy at zspec = 3.794. Together with existing Hubble Space Telescope imaging, these new observations from the JWST Advanced Deep Extragalactic Survey program enable a joint analysis of Ion1’s LyC, rest-frame UV, stellar, and dust emission with unprecedented detail. We report the first detection of dust emission at rest-frame ∼3 μm in a high-redshift LyC-emitting galaxy using MIRI/F1500W. Our analysis suggests a porous distribution of dust in Ion1, with regions exhibiting evidence of dust deficit coinciding both with LyC-emitting regions and with the peak of Hα emission. Furthermore, multiband NIRCam imaging reveals a strong far-UV-to-optical color gradient, where LyC-emitting regions appear significantly bluer than the rest of Ion1. Spatially resolved spectral energy distribution fitting confirms that this color gradient is primarily driven by spatially varying dust attenuation. Together, these findings suggest that Ion1’s LyC emission originates from a compact star-forming complex near its stellar-light centroid, where stellar feedback carves out low-H i-column-density channels, facilitating LyC escape. However, only a fraction of these LyC photons—specifically those along sightlines with minimal H i obscuration—ultimately escape and reach observers. This work underscores the critical role of dust and neutral gas geometry in shaping LyC escape in galaxies at high redshifts. Anisotropic LyC escape may be a common feature in the early Universe, which must be properly incorporated to constrain the epoch of reionization.
• Lola Danhaive, A., Tacchella, S., Übler, H., De Graaff, A., Egami, E., Johnson, B. D., Sun, F., Arribas, S., Bunker, A. J., Carniani, S., Jones, G. C., Maiolino, R., Mcclymont, W., Parlanti, E., Simmonds, C., Villanueva, N. C., Baker, W. M., Jaffe, D. T., Eisenstein, D., , Hainline, K., et al. (2025). The dawn of discs: unveiling the turbulent ionized gas kinematics of the galaxy population at z ∼ 4-6 with JWST/NIRCam grism spectroscopy. Monthly Notices of the Royal Astronomical Society, 543(Issue 4). doi:10.1093/mnras/staf1540
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  Recent studies of gas kinematics at high redshift have reported discy systems that appear to challenge models of galaxy formation, but it is unclear whether they are representative of the underlying galaxy population. We present the first statistical sample of spatially resolved ionized gas kinematics at high redshift, comprised of 213 H α emitters in GOODS-S and GOODS-N at redshifts z ≈3.9-6.5, observed with James Webb Space Telescope /NIRCam slitless spectroscopy and imaging from JADES, FRESCO, and CONGRESS. The sample probes two orders of magnitude in stellar mass (log ( M∗ [M⊙]) ≈8-10) and star formation rate (SFR ≈0 . 3-100 M⊙yr-1 ), and is representative down tolog ( M∗ [M⊙]) ≈9. Using a novel inference tool, GEKO, we model the grism data to measure morphological and kinematic properties of the ionized gas, as probed by H α. Our results are consistent with a decrease of the rotational support v/σ0 and increase of the velocity dispersion σ0 with redshift, when compared to z < 3, with σ0 ≈100 km s-1 and v/σ0 ≈1-2 at z ≈3.9-6.5. We study the relations between σ0 and v/σ0, and different star formation tracers and find a large scatter and diversity, with the most significant correlation between σ0 and SFR. We find no evolution of the fraction of rotationally supported systems (v/σ0 > 1) from z ∼5.5 to z ∼4.5, measured at f = (34 ±5)per cent in both redshift bins, for galaxies with masses 9
• Manzoni, G., Broadhurst, T., Lim, J., Liu, T., Smoot, G., Baugh, C. M., Tompkins, S., Windhorst, R., Driver, S., Carleton, T., Frye, B., Fung, L., Zhang, J., Cohen, S. H., Conselice, C. J., Grogin, N. A., Jansen, R. A., Koekemoer, A. M., Ortiz, R., , Pirzkal, N., et al. (2025). Explaining JWST Counts with Galaxy Formation Models. Astrophysical Journal, 988(Issue 2). doi:10.3847/1538-4357/ade700
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  A distinct power-law break is apparent at mAB ∼ 21 in the deep near-infrared PEARLS-JWST galaxy counts. The break becomes more pronounced at longer wavelengths, with the slope flattening smoothly with apparent magnitude in the shortest band used at 0.9 μm, and trending toward an increasingly broken slope by the longest wavelength passband of JWST’s Near Infrared Camera, 4.4 μm. This behaviour is remarkably well predicted by the GALFORM semi-analytical model of galaxy formation. We use the model to diagnose the origin of this behaviour. The features that are responsible for the break are (1) the inherent break in the luminosity function (LF); (2) the change in the volume element with redshift; (3) the redshift-dependent nature of the k-correction (with 1 contributing to the existence of the break and 2-3 contributing to its shape). We study the contribution to these effects by their morphology using the bulge-to-total stellar mass ratio. The way in which bulge-dominated galaxies populate the bright end of the LF while disk-dominated galaxies dominate the faint end is preserved in the galaxy number counts, with a characteristic stellar mass at a break of ∼1010M⊙. The shape of the number counts is mainly driven by galaxies with relatively low redshift (z ≲ 2) for a limit of mAB ≲ 28. We give a comprehensive description of why the galaxy number counts in the near-infrared PEARLS-JWST observation look the way they do and which population of galaxies is dominant at each apparent magnitude.
• Marshall, M. A., Windhorst, R. A., Ferrami, G., Willner, S. P., Del Carmen Polletta, M., Keel, W. C., Fazio, G. G., Cohen, S. H., Carleton, T., Jansen, R. A., Honor, R., Ortiz, R., Summers, J., D’Silva, J. C., Koekemoer, A. M., Coe, D., Conselice, C. J., Diego, J. M., Driver, S. P., , Frye, B., et al. (2025). JWST’s PEARLS: A z ≃ 6 quasar in a train-wreck galaxy merger system. Astronomy and Astrophysics, 702. doi:10.1051/0004-6361/202554307
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  We present JWST NIRSpec integral field spectroscopy observations of the z = 5.89 quasar NDWFS J1425+3254 from 0.6–5.3 μm, covering the rest-frame ultraviolet and optical at a spectral resolution of R ∼ 100. The quasar has a black hole mass of MBH = (1.4+3.1−1.0) × 109 M☉ and an Eddington ratio of L Bol/L Edd = 0.3+0.6−0.2, as implied from the broad Balmer Hα and Hβ lines. The quasar host has significant ongoing obscured star formation, as well as a quasar-driven outflow with velocity 6050+460−630 km s−1 and ionised outflow rate of 1650+130−1230 M☉ yr−1. This is possibly one of the most extreme outflows in the early Universe. The data also reveal that two companion galaxies are merging with the quasar host. The north-eastern companion galaxy is relatively old and very massive, with a luminosity-weighted stellar age of 65+9−4 Myr, stellar mass of (3.6+0.6−0.3 #x00D7; 1011 M☉, and star-formation rate (SFR) of ∼15–30 M☉ yr−1. A bridge of gas connects this companion galaxy and the host, confirming their ongoing interaction. A second merger is occurring between the quasar host and a much younger companion galaxy to the south, with a stellar age of 6.7 ± 1.8 Myr, stellar mass of (1.9 ± 0.4)×1010 M☉, and SFR of ∼40–65 M☉ yr−1. There is also another galaxy in the field, likely in the foreground at z = 1.135, which could be gravitationally lensing the quasar with a magnification of 1 < μ < 2 and, thus, < 0.75 mag. Overall, the system is a ‘train-wreck’ merger of three galaxies, with star formation and extreme quasar activity that were likely triggered by these ongoing interactions.
• Rinaldi, P., Bonaventura, N., Rieke, G. H., Alberts, S., Caputi, K. I., Baker, W. M., Baum, S., Bhatawdekar, R., Bunker, A. J., Carniani, S., Curtis-Lake, E., D’Eugenio, F., Egami, E., Ji, Z., Johnson, B. D., Hainline, K., Helton, J. M., Lin, X., Lyu, J., , Ma, Z., et al. (2025). Not Just a Dot: The Complex UV Morphology and Underlying Properties of Little Red Dots. Astrophysical Journal, 992(Issue 1). doi:10.3847/1538-4357/adfa10
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  We analyze 99 photometrically selected Little Red Dots (LRDs) at z ≈ 4–8 in the GOODS fields, leveraging ultradeep JADES NIRCam short-wavelength (SW) data. Among the 99 selected LRDs, we examine the morphology of 30. The remaining 69 appear predominantly compact, with sizes ≲400 pc and no extended components even in stacked SW images. However, their unresolved nature may partly reflect current depth limitations, which could prevent the detection of faint diffuse components. Among the 30 morphologically analyzed LRDs, 50% show multiple associated components, while the rest exhibit highly asymmetric structures, despite appearing as single sources. This diversity in rest-frame UV morphologies may point to interactions or strong internal feedback. We find median stellar masses of log 10 (M⋆/M⊙) = 9.07−0.08+0.11 for pure stellar models with AV ≈ 1.16−0.21+0.11 mag, and log10(M⋆/M⊙) = 9.67−0.27+0.17 for models including active galactic nuclei (AGNs) with AV ≈ 2.74−0.71+0.55 mag, in line with recent studies suggesting higher masses and dust content for AGN-fitted LRDs. NIRSpec spectra are available for 15 sources, six of which are also in the morphological sample. Broad Hα is detected in 40% (FWHM = 1200–2900 kms−1), and one source shows broad Hβ emission. Emission line ratios indicate a composite nature, consistent with both AGN and stellar processes. Altogether, these results suggest that LRDs are a mixed population, and their rest-frame UV morphology reflects this complexity. Morphological studies of larger samples could provide a new way to understand what drives their properties and evolution.
• Saikia, P., Wrzosek, R., Gelfand, J., Brisken, W., Cotton, W., Willner, S. P., Gim, H. B., Windhorst, R. A., Estrada-Carpenter, V., Katkov, I. Y., Zaw, I., Nicandro Rosenthal, M. J., Shafi, H., Kellermann, K., Condon, J., Koekemoer, A. M., Conselice, C. J., Ortiz, R., Willmer, C. N., , Frye, B., et al. (2025). Peering into the Heart of Darkness with VLBA: Radio-quiet Active Galactic Nucleus in the JWST North Ecliptic Pole Time-domain Field. Astrophysical Journal, 989(Issue 1). doi:10.3847/1538-4357/ade709
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  We present initial results from the 4.8 GHz Very Long Baseline Array (VLBA) survey of the JWST North Ecliptic Pole Time-Domain Field (TDF). From 106 radio sources found in the Karl G. Jansky Very Large Array (VLA) observations in the TDF, we detected 12 sources (∼11% detection rate) at ∼3.3 μJy rms sensitivity and ∼4 mas resolution. Most detections exhibit parsec-scale emission (less than 40 pc) with high VLBA/VLA flux density ratios and brightness temperatures exceeding 105 K, confirming nonthermal active galactic nucleus (AGN) activity. Spectral indices α ≳ −0.5 correlate with higher VLBA/VLA flux ratios, consistent with synchrotron emission from AGN coronae or jets. In the majority of our sources, star formation contributes less than 50% of the total VLBA radio emission, with a few cases where the emission is almost entirely AGN driven. Although the radio emission from radio quiet AGN is thought to be primarily driven by star formation, our VLBA observations confirm that there is also often a contribution at various levels from black hole driven AGN. Eight VLBA detections have JWST/NIRCam counterparts, predominantly early-type, bulge-dominated galaxies, which we use to get an estimate of the redshift and star formation rate (SFR). Wide-field Infrared Survey Explorer colors indicate that VLBA detections are either AGN or intermediate-disk-dominated systems, while VLBA nondetections correspond to extended, star-forming galaxies. We compare SFRs derived from previous SCUBA-2 850 μm observations with new JWST-based estimates, and discuss the observed discrepancies, highlighting JWST’s improved capability to disentangle AGN activity from star formation.
• Sun, Y., Lyu, J., Rieke, G. H., Ji, Z., Sun, F., Zhu, Y., Bunker, A. J., Cargile, P. A., Circosta, C., D’Eugenio, F., Egami, E., Hainline, K., Helton, J. M., Rinaldi, P., Robertson, B. E., Scholtz, J., Shivaei, I., Stone, M. A., Tacchella, S., , Williams, C. C., et al. (2025). No Evidence for a Significant Evolution of M•-M. Relation in Massive Galaxies up to z∼4. Astrophysical Journal, 978(Issue 1). doi:10.3847/1538-4357/ad973b
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  Over the past two decades, tight correlations between black hole masses (M•) and their host galaxy properties have been firmly established for massive galaxies (with stellar mass log ( M * / M ⊙ ) ≳ 10 ) at low-z (z < 1), indicating coevolution of supermassive black holes and galaxies. However, the situation at high-z, especially beyond cosmic noon (z ≳ 2.5), is controversial. With a combination of JWST Near Infrared Camera (NIRCam)/wide field slitless spectroscopy (WFSS) from FRESCO, CONGRESS and deep multiband NIRCam/image data from JADES in the GOODS fields, we study the black-hole-to-galaxy mass relation at z ∼ 1-4. After identifying 18 broad-line active galactic nuclei (AGNs) at 1 < z < 4 (with 8 at z > 2.5) from the WFSS data, we measure their black hole masses based on broad near-infrared lines (Paα, Paβ, and He i λ10833 Å), and constrain their stellar masses from AGN-galaxy image decomposition or spectral energy distribution decomposition. Taking account of the observational biases, the intrinsic scatter of the M•−M* relation, and the errors in mass measurements, we find no significant difference in the M•/M* ratio for 2.5 < z < 4 compared to that at lower redshifts (1 < z < 2.5), suggesting no evolution of the M•−M* relation at log ( M * / M ⊙ ) ≳ 10 up to z ∼ 4.
• Sun, Y., Rieke, G. H., Lyu, J., Stone, M. A., Ji, Z., Rinaldi, P., Willmer, C. N., & Zhu, Y. (2025). Evolution of the M∗-MBH Relation from z ∼ 6 to the Present Epoch. Astrophysical Journal, 983(Issue 2). doi:10.3847/1538-4357/adc250
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  The ratio between the stellar mass of a galaxy, M*, and that of its central supermassive black hole (SMBH), M•, the “Magorrian” relationship, traces their coevolution. JWST observations have suggested significant evolution in M•/M* relative to local scaling relationships both in low-mass galaxies and in quasars at z ≥ 4. We test this possibility by (1) determining the preferred M•/M* scaling relation among those proposed locally, and (2) providing uniform estimates of host galaxy stellar mass. These steps reduce the prominence of the reported evolution. We then apply Monte Carlo simulations to account for observational biases. We still find a significant increase over the local scaling relation in M•/M* for z ≥ 4 SMBHs in very low-mass galaxies ( log ( M * / M ⊙ ) < 10 ). However, similarly high values of M•/M* are also found in low-mass galaxies at z ∼ 0.5-3, which may be common at cosmic noon. Nonetheless, galaxies with similar behavior are rare locally and not accounted for in the local scaling relations. In contrast, z ∼ 6 quasars can have M•/M* well above the value given by the local relation, but they can be explained as extreme cases still within the scaling relation for their higher-mass host galaxies. Black holes in some of them and in the low-mass systems may be undergoing episodes of very high accretion that result in high M•/M* but that will be followed by quiescent periods when growth of the host drives the systems toward more typical M•/M* values.
• Tacchella, S., McClymont, W., Scholtz, J., Maiolino, R., Ji, X., Villanueva, N. C., Charlot, S., D’Eugenio, F., Helton, J. M., Williams, C. C., Witstok, J., Bhatawdekar, R., Carniani, S., Chevallard, J., Curti, M., Hainline, K., Ji, Z., Johnson, B. D., Leja, J., , Li, Y., et al. (2025). Resolving the nature and putative nebular emission of GS9422: an obscured AGN without exotic stars. Monthly Notices of the Royal Astronomical Society, 540(Issue 1). doi:10.1093/mnras/staf718
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  Understanding the sources that power nebular emission in high-redshift galaxies is fundamentally important not only for shedding light on to the drivers of reionization, but to constrain stellar populations and the growth of black holes. Here, we focus on an individual object, GS9422, a galaxy at zspec = 5.943 with exquisite data from the JWST Advanced Deep Extragalactic Survey (JADES), JWST Extragalactic Medium-band Survey (JEMS), and First Reionization Epoch Spectroscopically Complete Observations (FRESCO) surveys, including 14-band JWST/NIRCam photometry and deep NIRSpec prism and grating spectroscopy. We map the continuum emission and nebular emission lines across the galaxy on 0.2-kpc scales. GS9422 has been claimed to have nebular-dominated continuum and an extreme stellar population with top-heavy initial mass function. We find clear evidence for different morphologies in the emission lines, the rest-ultraviolet and rest-optical continuum emission, demonstrating that the full continuum cannot be dominated by nebular emission. While multiple models reproduce the spectrum reasonably well, our preferred model with a type-2 active galactic nucleus (AGN) and local damped Lyα (DLA) clouds can explain both the spectrum and the wavelength-dependent morphology. The AGN powers the off-planar nebular emission, giving rise to the Balmer jump and the emission lines, including Lyα, which therefore does not suffer DLA absorption. A central, young stellar component dominates the rest-UV emission and – together with the DLA clouds – leads to a spectral turn over. A disc-like, older stellar component explains the flattened morphology in the rest-optical continuum. We conclude that GS9422 is consistent with being a normal galaxy with an obscured, type-2 AGN – a simple scenario, without the need for exotic stellar populations.
• Westcott, L., Conselice, C. J., Harvey, T., Austin, D., Adams, N., Ferrari, F., Ferreira, L., Trussler, J., Li, Q., Rusakov, V., Duan, Q., Harris, H., Goolsby, C., Broadhurst, T. J., Coe, D., Cohen, S. H., Driver, S. P., D’Silva, J. C., Frye, B., , Grogin, N. A., et al. (2025). EPOCHS. XI. The Structure and Morphology of Galaxies in the Epoch of Reionization to z ∼ 12.5. Astrophysical Journal, 983(Issue 2). doi:10.3847/1538-4357/adb968
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  We present a structural analysis of 520 galaxy candidates at 6.5 < z < 12.5 with a signal-to-noise ratio of >10σ in the F444W filter taken from the EPOCHS v1 sample, consisting of uniformly reduced deep JWST NIRCam data covering the CEERS, JADES GOODS-S, NGDEEP, SMACS-0723, GLASS, and PEARLS surveys. We use standard software to fit single Sérsic models to each galaxy in the rest-frame optical and extract their parametric structural parameters (Sérsic index, half-light radius, and axis ratio) and Morfometryka to measure their nonparametric concentration and asymmetry parameters. We find a wide range of sizes for these early galaxies, with galaxy sizes overall continuing to become progressively smaller in the high-redshift regime, following R e = 2.12 ± 0.28 1 + z − 0.67 ± 0.06 kpc. We further find a galaxy size-mass correlation up to z ∼ 12, with galaxies of a given mass also becoming smaller. Using nonparametric methods, we find that galaxy merger fractions, classified through asymmetry parameters, at these redshifts remain consistent with those in the literature, maintaining a value of fm ∼ 0.12 ± 0.07 showing little dependence with redshift when combined with the literature at z > 4. We find that galaxies that are smaller in size also appear rounder, with an excess of high axis ratio objects. Finally, we artificially redshift a subsample of our objects to determine how robust the observational trends we see are, determining that the observed trends are due to real evolutionary effects, rather than being a consequence of redshift effects.
• Whitler, L., Stark, D. P., Topping, M. W., Robertson, B., Rieke, M., Hainline, K. N., Endsley, R., Chen, Z., Baker, W. M., Bhatawdekar, R., Bunker, A. J., Carniani, S., Charlot, S., Chevallard, J., Curtis-Lake, E., Egami, E., Eisenstein, D. J., Helton, J. M., Ji, Z., , Johnson, B. D., et al. (2025). The z ≳ 9 Galaxy UV Luminosity Function from the JWST Advanced Deep Extragalactic Survey: Insights into Early Galaxy Evolution and Reionization. Astrophysical Journal, 992(Issue 1). doi:10.3847/1538-4357/adfddc
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  The high-redshift UV luminosity function provides important insights into the evolution of early galaxies. JWST has revealed an unexpectedly large population of bright (MUV ≲ −20) galaxies at z ≳ 10, implying fundamental changes in the star-forming properties of galaxies at increasingly early times. However, constraining the fainter population (MUV ≳ −18) has been more challenging. In this work, we present the z ≳ 9 UV luminosity function from the JWST Advanced Deep Extragalactic Survey. We calculate the UV luminosity function from several hundred z ≳ 9 galaxy candidates that reach UV luminosities of MUV ∼ −17 in redshift bins of z ∼ 8.5–12 (309 candidates) and z ∼ 12–16 (63 candidates). We search for candidates at z ∼ 16–22.5 and find none. We also estimate the z ∼ 14–16 luminosity function from the z ≥ 14 subset of the z ∼ 12–16 sample. Consistent with other measurements, we find an excess of bright galaxies that is in tension with many theoretical models, especially at z ≳ 12. However, we also find high number densities at −18 ≲ MUV ≲ −17, suggesting that there is a larger population of faint galaxies than expected, as well as bright ones. From our parametric fits for the luminosity function, we find steep faint-end slopes of −2.5 ≲ α ≲ −2.3, suggesting a large population of faint (MUV ≳ −17) galaxies. Combined, the high normalization and steep faint-end slope of the luminosity function could imply that the reionization process is appreciably underway as early as z = 10.
• Witstok, J., Jakobsen, P., Maiolino, R., Helton, J. M., Johnson, B. D., Robertson, B. E., Tacchella, S., Cameron, A. J., Smit, R., Bunker, A. J., Saxena, A., Sun, F., Alberts, S., Arribas, S., Baker, W. M., Bhatawdekar, R., Boyett, K., Cargile, P. A., Carniani, S., , Charlot, S., et al. (2025). Witnessing the onset of reionization through Lyman-α emission at redshift 13. Nature, 639(Issue 8056). doi:10.1038/s41586-025-08779-5
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  Cosmic reionization began when ultraviolet (UV) radiation produced in the first galaxies began illuminating the cold, neutral gas that filled the primordial Universe1,2. Recent James Webb Space Telescope (JWST) observations have shown that surprisingly UV-bright galaxies were in place beyond redshift z = 14, when the Universe was less than 300 Myr old3, 4–5. Smooth turnovers of their UV continua have been interpreted as damping-wing absorption of Lyman-α (Ly-α), the principal hydrogen transition6, 7, 8–9. However, spectral signatures encoding crucial properties of these sources, such as their emergent radiation field, largely remain elusive. Here we report spectroscopy from the JWST Advanced Deep Extragalactic Survey (JADES10) of a galaxy at redshift z = 13.0 that reveals a singular, bright emission line unambiguously identified as Ly-α, as well as a smooth turnover. We observe an equivalent width of EWLy-α > 40 Å (rest frame), previously only seen at z < 9 where the intervening intergalactic medium becomes increasingly ionized11. Together with an extremely blue UV continuum, the unexpected Ly-α emission indicates that the galaxy is a prolific producer and leaker of ionizing photons. This suggests that massive, hot stars or an active galactic nucleus have created an early reionized region to prevent complete extinction of Ly-α, thus shedding new light on the nature of the earliest galaxies and the onset of reionization only 330 Myr after the Big Bang.
• Witstok, J., Maiolino, R., Smit, R., Jones, G. C., Bunker, A. J., Helton, J. M., Johnson, B. D., Tacchella, S., Saxena, A., Arribas, S., Bhatawdekar, R., Boyett, K., Cameron, A. J., Cargile, P. A., Carniani, S., Charlot, S., Chevallard, J., Curti, M., Curtis-Lake, E., , D’Eugenio, F., et al. (2025). JADES: primaeval Lyman α emitting galaxies reveal early sites of reionization out to redshift z ~ 9. Monthly Notices of the Royal Astronomical Society, 536(Issue 1). doi:10.1093/mnras/stae2535
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  Given the sensitivity of the resonant Lyman α (Ly α) transition to absorption by neutral hydrogen, observations of Ly α emitting galaxies (LAEs) have been widely used to probe the ionizing capabilities of reionization-era galaxies and their impact on the intergalactic medium (IGM). However, prior to JWST our understanding of the contribution of fainter sources and of ionized ‘bubbles’ at earlier stages of reionization remained uncertain. Here, we present the characterization of three exceptionally distant LAEs at z > 8, newly discovered by JWST/Near-Infrared Spectrograph in the JADES survey. These three similarly bright (MUV ≈ −20 mag) LAEs exhibit small Ly α velocity offsets from the systemic redshift, (Formula presented) 200 km s−1, yet span a range of Ly α equivalent widths (15, 31, and 132 Å). The former two show moderate Ly α escape fractions (fesc, Lyα ≈ 10 per cent), whereas Ly α escapes remarkably efficiently from the third (fesc, Lyα ≈ 72 per cent), which moreover is very compact (half-light radius of 90 ± 10 pc). We find these LAEs are low-mass galaxies dominated by very recent, vigorous bursts of star formation accompanied by strong nebular emission from metal-poor gas. We infer the two LAEs with modest fesc, Lyα, one of which reveals evidence for ionization by an active galactic nucleus, may have reasonably produced small ionized bubbles preventing complete IGM absorption of Ly α. The third, however, requires a ∼3 physical Mpc bubble, indicating faint galaxies have contributed significantly. The most distant LAEs thus continue to be powerful observational probes into the earlier stages of reionization.
• Wu, Z., Eisenstein, D. J., Johnson, B. D., Jakobsen, P., Alberts, S., Arribas, S., Baker, W. M., Bunker, A. J., Carniani, S., Charlot, S., Chevallard, J., Curti, M., Curtis-Lake, E., D’Eugenio, F., Hainline, K., Helton, J. M., Hsiao, T. Y., Ji, X., Ji, Z., , Looser, T. J., et al. (2025). JADES-GS-z14-1: A Compact, Faint Galaxy at z ≈ 14 with Weak Metal Lines from Extremely Deep JWST MIRI, NIRCam, and NIRSpec Observations. Astrophysical Journal, 992(Issue 2). doi:10.3847/1538-4357/ae01a1
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  JWST has shed light on galaxy formation and metal enrichment within 300 Myr of the Big Bang. While luminous galaxies at z > 10 often show significant [O III] λλ4959, 5007 emission lines, it remains unclear whether such features are prevalent among fainter, more typical galaxies due to observational limits. We present deep imaging and spectroscopy of JADES-GS-z14-1 at zspec = 13.86+0.05 _0.04, currently the faintest spectroscopically confirmed galaxy at z ≈ 14. It serendipitously received 70.7 hr of MIRI/F770W imaging in the JWST Advanced Deep Extragalactic Survey (JADES), the deepest MIRI exposure for any high-redshift galaxy to date. Nonetheless, we detect only tentative F770W emission of 7.9 ± 2.8 nJy at 2.8σ significance, constraining the total equivalent width of [O III] λλ4959, 5007 + Hβ to 520+380 _400 Å, weaker than most z > 10 galaxies with MIRI detections. This source is unresolved across 16 NIRCam bands, implying a physical radius ≲50 pc. NIRSpec/PRISM spectroscopy totaling 56 hr reveals no rest-frame ultraviolet emission lines above 3σ. Stellar population synthesis suggests a stellar mass ∼4 × 107 M☉ and a star formation rate ∼2 M☉ yr−1. The absence of strong metal emission lines despite intense star formation suggests a gas-phase metallicity below 10% solar and potentially a high escape fraction of ionizing photons. These deep observations provide rare constraints on faint, early galaxies, tracing the onset of chemical enrichment and ionization in the early Universe.
• Zhu, Y., Alberts, S., Lyu, J., Morrison, J., Rieke, G. H., Sun, Y., Helton, J. M., Ji, Z., Bhatawdekar, R., Bonaventura, N., Bunker, A. J., Lin, X., Rieke, M. J., Rinaldi, P., Shivaei, I., Willmer, C. N., & Zhang, J. (2025). SMILES: Potentially Higher Ionizing Photon Production Efficiency in Overdense Regions. Astrophysical Journal, 986(Issue 1). doi:10.3847/1538-4357/add263
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  The topology of reionization and the environments where galaxies efficiently produce ionizing photons are key open questions. For the first time, we investigate the trend between ionizing photon production efficiency, ξion, and galaxy overdensity, log ( 1 + δ ) . We analyze the ionizing properties of 79 galaxies between 1.0 < z < 5.2 using JWST NIRSpec medium-resolution spectra from the Systematic Mid-infrared Instrument Legacy Extragalactic Survey (SMILES) program. Among these, 67 galaxies have Hα coverage, spanning 1.0 < z < 3.1. The galaxy overdensity, log ( 1 + δ ) , is measured using the JADES photometric catalog, which covers the SMILES footprint. For the subset with Hα coverage, we find that log ξ ion is positively correlated with log ( 1 + δ ) , with a slope of 0.9 4 − 0.46 + 0.46 . Additionally, the mean ξion for galaxies in overdense regions ( log ( 1 + δ ) > 0.1 ) is 2.43 times that of galaxies in lower density regions ( log ( 1 + δ ) < 0.1 ). This strong trend is found to be independent of redshift evolution. Furthermore, our results confirm the robust correlations between ξion and the rest-frame equivalent widths of the [O iii] or Hα emission lines. Our results suggest that galaxies in high-density regions are efficient producers of ionizing photons.
• Zhu, Y., Rieke, M. J., Ji, Z., Simmonds, C., Sun, F., Sun, Y., Alberts, S., Bhatawdekar, R., Bunker, A. J., Cargile, P. A., Carniani, S., de Graaff, A., Hainline, K., Helton, J. M., Jones, G. C., Lyu, J., Rieke, G. H., Rinaldi, P., Robertson, B., , Scholtz, J., et al. (2025). A Systematic Search for Galaxies with Extended Emission Lines and Potential Outflows in JADES Medium-band Images. Astrophysical Journal, 986(Issue 2). doi:10.3847/1538-4357/add2f4
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  For the first time, we present a systematic search for galaxies with extended emission lines and potential outflow features using JWST medium-band images in the GOODS South field. This is done by comparing the morphology in medium-band images to adjacent continuum and UV bands. We look for galaxies that have a maximum extent 50% larger, an excess area 30% greater, or an axis ratio difference of more than 0.3 in the medium band compared to the reference bands. After visual inspection, we find 326 candidate galaxies at 1.4 < z < 8.4, with a peak in the population near cosmic noon, benefiting from the good coverage of the medium-band filters. By fitting their spectral energy distributions, we find that the candidate galaxies are at least 20% more bursty in their star-forming activity and have 50% more young stellar populations compared to a control sample selected based on the continuum band flux. Additionally, these candidates exhibit a significantly higher production rate of ionizing photons. We further find that candidates hosting known active galactic nuclei (AGN) produce extended emission that is more anisotropic compared to non-AGN candidates. A few of our candidates have been spectroscopically confirmed to have prominent outflow signatures through NIRSpec observations, showcasing the robustness of the photometric selection. Future spectroscopic follow-up will better help verify and characterize the kinematics and chemical properties of these systems.
• Adams, N. J., Conselice, C. J., Austin, D., Harvey, T., Ferreira, L., Trussler, J., Juod{\v{z}balis}, I., Li, Q., Windhorst, R., Cohen, S. H., Jansen, R. A., Summers, J., Tompkins, S., Driver, S. P., Robotham, A., D'Silva, J. C., Yan, H., Coe, D., Frye, B., , Grogin, N. A., et al. (2024). EPOCHS. II. The Ultraviolet Luminosity Function from 7.5 < z < 13.5 Using 180 arcmin$^2$ of Deep, Blank Fields from the PEARLS Survey and Public JWST Data. \apj, 965(2), 169.
• Alberts, S., Lyu, J., Shivaei, I., Rieke, G. H., P{\'erez-Gonz\'alez}, P. G., Bonaventura, N., Zhu, Y., Helton, J. M., Ji, Z., Morrison, J., Robertson, B. E., Stone, M. A., Sun, Y., Williams, C. C., & Willmer, C. N. (2024). SMILES Initial Data Release: Unveiling the Obscured Universe with MIRI Multiband Imaging. \apj, 976(2), 224.
• Alberts, S., Lyu, J., Shivaei, I., Rieke, G., Bonaventura, N., Zhu, Y., Helton, J., Ji, Z., Morrison, J., Robertson, B., Stone, M., Sun, Y., Williams, C., Willmer, C., & Pérez-González, P. (2024). SMILES Initial Data Release: Unveiling the Obscured Universe with MIRI Multiband Imaging. Astrophysical Journal, 976(2). doi:10.3847/1538-4357/ad7396
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  The James Webb Space Telescope is revolutionizing our view of the Universe through unprecedented sensitivity and resolution in the infrared, with some of the largest gains realized at its longest wavelengths. We present the Systematic Mid-infrared Instrument (MIRI) Legacy Extragalactic Survey (SMILES), an eight-band MIRI survey with Near-Infrared Spectrograph spectroscopic follow-up in the GOODS-S/HUDF region. SMILES takes full advantage of MIRI’s continuous coverage from 5.6 to 25.5 μm over an ∼34 arcmin2 area to greatly expand our understanding of the obscured Universe up to cosmic noon and beyond. This work, together with a companion paper by G. Rieke et al., covers the SMILES science drivers and technical design, early results with SMILES, data reduction, photometric catalog creation, and the first data release. As part of the discussion on early results, we additionally present a high-level science demonstration on how MIRI’s wavelength coverage and resolution will advance our understanding of cosmic dust using the full range of polycyclic aromatic hydrocarbon emission features from 3.3 to 18 μm. Using custom background subtraction, we produce robust reductions of the MIRI imaging that maximize the depths reached with our modest exposure times (∼0.6−2.2 ks per filter). Included in our initial data release are (1) eight MIRI imaging mosaics reaching depths of 0.2−18 μJy (5σ) and (2) a 5−25.5 μm photometric catalog with over 3000 sources. Building upon the rich legacy of extensive photometric and spectroscopy coverage of GOODS-S/HUDF from the X-ray to the radio, SMILES greatly expands our investigative power in understanding the obscured Universe.
• Alberts, S., Williams, C. C., Helton, J. M., Suess, K. A., Ji, Z., Shivaei, I., Lyu, J., Rieke, G., Baker, W. M., Bonaventura, N., Bunker, A. J., Carniani, S., Charlot, S., Curtis-Lake, E., D'Eugenio, F., Eisenstein, D. J., Graaff, A., Hainline, K. N., Hausen, R., , Johnson, B. D., et al. (2024). To High Redshift and Low Mass: Exploring the Emergence of Quenched Galaxies and Their Environments at 3 < z < 6 in the Ultra-deep JADES MIRI F770W Parallel. \apj, 975(1), 85.
• Alberts, S., Williams, C., Helton, J., Suess, K., Ji, Z., Shivaei, I., Lyu, J., Rieke, G., Baker, W., Bonaventura, N., Bunker, A., Carniani, S., Charlot, S., Curtis-Lake, E., Eisenstein, D., de Graaff, A., Hainline, K., Hausen, R., Johnson, B., , Maiolino, R., et al. (2024). To High Redshift and Low Mass: Exploring the Emergence of Quenched Galaxies and Their Environments at 3 < z < 6 in the Ultra-deep JADES MIRI F770W Parallel. Astrophysical Journal, 975(1). doi:10.3847/1538-4357/ad66cc
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  We present the robust selection of high-redshift quiescent galaxies (QG) and poststarburst (PSB) galaxies using ultra-deep NIRCam and MIRI imaging from the JWST Advanced Deep Extragalactic Survey (JADES). At 3 < z < 6, MIRI 7.7 μm imaging provides rest-frame J band, which is commonly used to break the degeneracy between old stellar populations and dust attenuation at lower redshifts. We identify 23 passively evolving galaxies in UVJ color space in a mass-limited (log M ⋆/M ⊙ ≥ 8.5) sample over 8.8 arcmin2. An evaluation of the contribution of the 7.7 μm shows that JADES-like NIRCam coverage (9+ photometric bands) can compensate for lacking the J band at these redshifts; however, more limited three-band selections perform better with MIRI. Our sample is characterized by rapid quenching timescales (∼100-600 Myr) with formation redshifts z f ≲ 9 and includes a potential record-holding massive QG at z phot = 5.33 − 0.17 + 0.16 and two QGs with evidence for significant residual dust content (A V ∼ 1-2). In addition, we present a large sample of 12 log M ⋆/M ⊙ = 8.5-9.5 PSBs, demonstrating that UVJ selection can be extended to low mass. An analysis of the environment of our sample reveals that the group known as the Cosmic Rose contains a massive QG and a dust-obscured star-forming galaxy (a so-called Jekyll and Hyde pair) plus three additional QGs within ∼20 kpc. Moreover, the Cosmic Rose is part of a larger overdensity at z ∼ 3.7, which contains 7/12 of our low-mass PSBs. Another four low-mass PSBs are members of an overdensity at z ∼ 3.4; this result strongly indicates low-mass PSBs are preferentially associated with overdense environments at z > 3.
• Baker, W., Tacchella, S., Johnson, B., Nelson, E., Suess, K., Curti, M., de Graaff, A., Ji, Z., Maiolino, R., Robertson, B., Scholtz, J., Alberts, S., Arribas, S., Boyett, K., Bunker, A., Carniani, S., Charlot, S., Chen, Z., Chevallard, J., , Curtis-Lake, E., et al. (2024). A core in a star-forming disc as evidence of inside-out growth in the early Universe. Nature Astronomy, 9(Issue 1). doi:10.1038/s41550-024-02384-8
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  The physical processes that establish the morphological evolution and the structural diversity of galaxies are key unknowns in extragalactic astrophysics. Here we report the finding of the morphologically mature galaxy JADES-GS+53.18343−27.79097, which existed within the first 700 million years of the Universe’s history. This star-forming galaxy with a stellar mass of 400 million solar masses consists of three components: a highly compact core with a half-light radius of less than 100 pc, an actively star-forming disc with a radius of about 400 pc and a star-forming clump, all of which show distinctive star-formation histories. The central stellar mass density of this galaxy is within a factor of 2 of the most massive present-day ellipticals, while being globally 1,000 times less massive. The radial profile of the specific star-formation rate is rising towards the outskirts. This evidence suggests a detection of the inside-out growth of a galaxy as a proto-bulge and a star-forming disc in the epoch of reionization.
• Barro, G., Rieke, G., Lyu, J., Rieke, M., Alberts, S., Williams, C., Hainline, K., Sun, F., Annunziatella, M., Baker, W., Bunker, A., Egami, E., Ji, Z., Johnson, B., Robertson, B., Rujopakarn, W., Shivaei, I., Tacchella, S., Willmer, C., , Willott, C., et al. (2024). What Is the Nature of Little Red Dots and what Is Not, MIRI SMILES Edition. Astrophysical Journal, 968(1). doi:10.3847/1538-4357/ad38bb
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  We study 31 little red dots (LRD) detected by JADES/NIRCam and covered by the SMILES/MIRI survey, of which ∼70% are detected in the two bluest MIRI bands and 40% in redder MIRI filters. The median/quartiles redshifts are z = 6.9 5.9 7.7 (55% spectroscopic). The spectral slopes flatten in the rest-frame near-infrared, consistent with a 1.6 μm stellar bump but bluer than direct pure emission from active galactic nuclei (AGN) tori. The apparent dominance of stellar emission at these wavelengths for many LRDs expedites stellar mass estimation: the median/quartiles are log M ⋆ / M ⊙ = 9.4 9.1 9.7 . The number density of LRDs is 10−4.0±0.1 Mpc−3, accounting for 14% ± 3% of the global population of galaxies with similar redshifts and masses. The rest-frame near-/mid-infrared (2-4 μm) spectral slope reveals significant amounts of warm dust (bolometric attenuation ∼3-4 mag). Our spectral energy distribution modeling implies the presence of 10 mag. We find a wide variety in the nature of LRDs. However, the best-fitting models for many of them correspond to extremely intense and compact starburst galaxies with mass-weighted ages 5-10 Myr, very efficient in producing dust, with their global energy output dominated by the direct (in the flat rest-frame ultraviolet and optical spectral range) and dust-recycled emission from OB stars with some contribution from an obscured AGN (in the infrared).
• Berkheimer, J. M., Carleton, T., Windhorst, R. A., Keel, W. C., Holwerda, B. W., Nonino, M., Cohen, S. H., Jansen, R. A., Coe, D., Conselice, C. J., Driver, S. P., Frye, B. L., Grogin, N. A., Koekemoer, A. M., Lucas, R. A., Marshall, M. A., Pirzkal, N., Robertson, C., Robotham, A., , Ryan, R. E., et al. (2024). JWST NIRCam Photometry: A Study of Globular Clusters Surrounding Bright Elliptical Galaxy VV 191a at z = 0.0513. \apjl, 964(2), L29.
• Bunker, A. J., Cameron, A. J., Curtis-Lake, E., Jakobsen, P., Carniani, S., Curti, M., Witstok, J., Maiolino, R., D'Eugenio, F., Looser, T. J., Willott, C., Bonaventura, N., Hainline, K., {\"Ubler}, H., Willmer, C. N., Saxena, A., Smit, R., Alberts, S., Arribas, S., , Baker, W. M., et al. (2024). JADES NIRSpec initial data release for the Hubble Ultra Deep Field: Redshifts and line fluxes of distant galaxies from the deepest JWST Cycle 1 NIRSpec multi-object spectroscopy. \aap, 690, A288.
• Bunker, A., Cameron, A., Curtis-Lake, E., Jakobsen, P., Carniani, S., Curti, M., Witstok, J., Maiolino, R., D'Eugenio, F., Looser, T., Willott, C., Bonaventura, N., Hainline, K., Willmer, C., Saxena, A., Smit, R., Alberts, S., Arribas, S., Baker, W., , Baum, S., et al. (2024). JADES NIRSpec initial data release for the Hubble Ultra Deep Field: Redshifts and line fluxes of distant galaxies from the deepest JWST Cycle 1 NIRSpec multi-object spectroscopy. Astronomy and Astrophysics, 690(Issue). doi:10.1051/0004-6361/202347094
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  We describe the NIRSpec component of the JWST Deep Extragalactic Survey (JADES), and provide deep spectroscopy of 253 sources targeted with the NIRSpec micro-shutter assembly in the Hubble Ultra Deep Field and surrounding GOODS-South. The multi-object spectra presented here are the deepest so far obtained with JWST, amounting to up to 28 hours in the low-dispersion (R~30- 300) prism, and up to 7 hours in each of the three medium-resolution R 1000 gratings and one high-dispersion grating, G395H (R 2700). Our low-dispersion and medium-dispersion spectra cover the wavelength range 0.6- 5.3 μm. We describe the selection of the spectroscopic targets, the strategy for the allocation of targets to micro-shutters, and the design of the observations. We present the public release of the reduced 2D and 1D spectra, and a description of the reduction and calibration process. We measure spectroscopic redshifts for 178 of the objects targeted extending up to z = 13.2. We present a catalogue of all emission lines detected at S/N > 5, and our redshift determinations for the targets. Combined with the first JADES NIRCam data release, these public JADES spectroscopic and imaging datasets provide a new foundation for discoveries of the infrared universe by the worldwide scientific community.
• Carleton, T., Ellsworth-Bowers, T., Windhorst, R. A., Cohen, S. H., Conselice, C. J., Diego, J. M., Zitrin, A., Archer, H. N., McIntyre, I., Kamieneski, P., Jansen, R. A., Summers, J., D'Silva, J. C., Koekemoer, A. M., Coe, D., Driver, S. P., Frye, B., Grogin, N. A., Marshall, M. A., , Nonino, M., et al. (2024). PEARLS: A Potentially Isolated Quiescent Dwarf Galaxy with a Tip of the Red Giant Branch Distance of 30 Mpc. \apjl, 961(2), L37.
• Carniani, S., Hainline, K., D'Eugenio, F., Eisenstein, D. J., Jakobsen, P., Witstok, J., Johnson, B. D., Chevallard, J., Maiolino, R., Helton, J. M., Willott, C., Robertson, B., Alberts, S., Arribas, S., Baker, W. M., Bhatawdekar, R., Boyett, K., Bunker, A. J., Cameron, A. J., , Cargile, P. A., et al. (2024). Spectroscopic confirmation of two luminous galaxies at a redshift of 14. \nat, 633(8029), 318-322.
• Carniani, S., Hainline, K., Eisenstein, D., Jakobsen, P., Witstok, J., Johnson, B., Chevallard, J., Maiolino, R., Helton, J., Willott, C., Robertson, B., Alberts, S., Arribas, S., Baker, W., Bhatawdekar, R., Boyett, K., Bunker, A., Cameron, A., Cargile, P., , Charlot, S., et al. (2024). Spectroscopic confirmation of two luminous galaxies at a redshift of 14. Nature, 633(8029). doi:10.1038/s41586-024-07860-9
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  The first observations of the James Webb Space Telescope (JWST) have revolutionized our understanding of the Universe by identifying galaxies at redshift z ≈ 13 (refs. 1–3). In addition, the discovery of many luminous galaxies at Cosmic Dawn (z > 10) has suggested that galaxies developed rapidly, in apparent tension with many standard models4–8. However, most of these galaxies lack spectroscopic confirmation, so their distances and properties are uncertain. Here we present JWST Advanced Deep Extragalactic Survey–Near-Infrared Spectrograph spectroscopic confirmation of two luminous galaxies at z=14.32−0.20+0.08 and z = 13.90 ± 0.17. The spectra reveal ultraviolet continua with prominent Lyman-α breaks but no detected emission lines. This discovery proves that luminous galaxies were already in place 300 million years after the Big Bang and are more common than what was expected before JWST. The most distant of the two galaxies is unexpectedly luminous and is spatially resolved with a radius of 260 parsecs. Considering also the very steep ultraviolet slope of the second galaxy, we conclude that both are dominated by stellar continuum emission, showing that the excess of luminous galaxies in the early Universe cannot be entirely explained by accretion onto black holes. Galaxy formation models will need to address the existence of such large and luminous galaxies so early in cosmic history.
• Curti, M., Maiolino, R., Curtis-Lake, E., Chevallard, J., Carniani, S., D'Eugenio, F., Looser, T. J., Scholtz, J., Charlot, S., Cameron, A., {\"Ubler}, H., Witstok, J., Boyett, K., Laseter, I., Sandles, L., Arribas, S., Bunker, A., Giardino, G., Maseda, M. V., , Rawle, T., et al. (2024). JADES: Insights into the low-mass end of the mass-metallicity-SFR relation at 3 < z < 10 from deep JWST/NIRSpec spectroscopy. \aap, 684, A75.
• D'Eugenio, F., Maiolino, R., Carniani, S., Chevallard, J., Curtis-Lake, E., Witstok, J., Charlot, S., Baker, W. M., Arribas, S., Boyett, K., Bunker, A. J., Curti, M., Eisenstein, D. J., Hainline, K., Ji, Z., Johnson, B. D., Kumari, N., Looser, T. J., Nakajima, K., , Nelson, E., et al. (2024). JADES: Carbon enrichment 350 Myr after the Big Bang. \aap, 689, A152.
• Diego, J. M., Adams, N. J., Willner, S. P., Harvey, T., Broadhurst, T., Cohen, S. H., Jansen, R. A., Summers, J., Windhorst, R. A., D'Silva, J. C., Koekemoer, A. M., Coe, D., Conselice, C. J., Driver, S. P., Frye, B., Grogin, N. A., Marshall, M. A., Nonino, M., Ortiz, R., , Pirzkal, N., et al. (2024). JWST's PEARLS: 119 multiply imaged galaxies behind MACS0416, lensing properties of caustic crossing galaxies, and the relation between halo mass and number of globular clusters at z = 0.4. \aap, 690, A114.
• Diego, J., Adams, N., Willner, S., Harvey, T., Broadhurst, T., Cohen, S., Jansen, R., Summers, J., Windhorst, R., D'Silva, J., Koekemoer, A., Coe, D., Conselice, C., Driver, S., Frye, B., Grogin, N., Marshall, M., Nonino, M., Ortiz, R., , Pirzkal, N., et al. (2024). JWST's PEARLS: 119 multiply imaged galaxies behind MACS0416, lensing properties of caustic crossing galaxies, and the relation between halo mass and number of globular clusters at z = 0.4. Astronomy and Astrophysics, 690(Issue). doi:10.1051/0004-6361/202349119
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  We present a new lens model for the z = 0.396 galaxy cluster MACS J0416.1 -2403 based on a previously known set of 77 spectroscop-ically confirmed, multiply imaged galaxies plus an additional set of 42 candidate multiply imaged galaxies from past HST and new JWST data. The new galaxies lack spectroscopic redshifts but have geometric and/or photometric redshift estimates that are presented here. The new model predicts magnifications and time delays for all multiple images. The full set of constraints totals 343, constituting the largest sample of multiple images lensed by a single cluster to date. Caustic-crossing galaxies lensed by this cluster are especially interesting. Some of these galaxies show transient events, most of which are interpreted as micro-lensing of stars at cosmological distances. These caustic-crossing arcs are expected to show similar events in future, deeper JWST observations. We provide time delay and magnification models for all these arcs. The time delays and the magnifications for different arcs are generally anti-correlated. In the major sub-halos of the cluster, the dark-matter mass from our lens model correlates well with the observed number of globular clusters, as expected from N-body simulations. This confirms earlier results, derived at lower redshifts, which suggest that globular clusters can be used as powerful mass proxies for the halo masses when lensing constraints are scarce or not available.
• Dressler, A., Rieke, M., Eisenstein, D., Stark, D. P., Burns, C., Bhatawdekar, R., Bonaventura, N., Boyett, K., Bunker, A. J., Carniani, S., Charlot, S., Hausen, R., Misselt, K., Tacchella, S., & Willmer, C. (2024). Building the First Galaxies\textemdashChapter 2. Starbursts Dominate the Star Formation Histories of 6 < z < 12 Galaxies. \apj, 964(2), 150.
• Endsley, R., Stark, D. P., Whitler, L., Topping, M. W., Johnson, B. D., Robertson, B., Tacchella, S., Alberts, S., Baker, W. M., Bhatawdekar, R., Boyett, K., Bunker, A. J., Cameron, A. J., Carniani, S., Charlot, S., Chen, Z., Chevallard, J., Curtis-Lake, E., Danhaive, A. L., , Egami, E., et al. (2024). The star-forming and ionizing properties of dwarf z 6-9 galaxies in JADES: insights on bursty star formation and ionized bubble growth. \mnras, 533(1), 1111-1142.
• Endsley, R., Stark, D., Whitler, L., Topping, M., Johnson, B., Robertson, B., Tacchella, S., Alberts, S., Baker, W., Bhatawdekar, R., Boyett, K., Bunker, A., Cameron, A., Carniani, S., Charlot, S., Chen, Z., Chevallard, J., Curtis-Lake, E., Danhaive, A., , Egami, E., et al. (2024). The star-forming and ionizing properties of dwarf z ~ 6-9 galaxies in JADES: Insights on bursty star formation and ionized bubble growth. Monthly Notices of the Royal Astronomical Society, 533(1). doi:10.1093/mnras/stae1857
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  Reionization is thought to be driven by faint star-forming galaxies, but characterizing this population has long remained very challenging. Here, we utilize deep nine-band JADES (JWST Advanced Deep Extragalactic Survey)/NIRCam (Near-Infrared Camera) imaging to study the star-forming and ionizing properties of 756 galaxies, including hundreds of very ultraviolet (UV)-faint objects (). The faintest () galaxies in our sample typically have stellar masses of and young light-weighted ages (50 Myr), though some show strong Balmer breaks implying much older ages (500 Myr). We find no evidence for extremely massive galaxies () in our sample. We infer a strong (factor 2) decline in the typical [O iii]H equivalent widths (EWs) towards very faint galaxies, yet a weak UV luminosity dependence on the H EWs at. We demonstrate that these EW trends can be explained if fainter galaxies have systematically lower metallicities as well as more recently declining star formation histories relative to the most UV-luminous galaxies. Our data provide evidence that the brightest galaxies are frequently experiencing a recent strong upturn in star formation rate. We also discuss how the EW trends may be influenced by a strong correlation between and Lyman continuum escape fraction. This alternative explanation has dramatically different implications for the contribution of galaxies along the luminosity function to cosmic reionization. Finally, we quantify the photometric overdensities around two strong Ly emitters. One Ly emitter lies close to a strong photometric overdensity, while the other shows no significant nearby overdensity, perhaps implying that not all strong Ly emitters reside in large ionized bubbles.
• Frye, B. L., Pascale, M., Pierel, J., Chen, W., Foo, N., Leimbach, R., Garuda, N., Cohen, S. H., Kamieneski, P. S., Windhorst, R. A., Koekemoer, A. M., Kelly, P., Summers, J., Engesser, M., Liu, D., Furtak, L. J., Polletta, M., Harrington, K. C., Willner, S., , Diego, J. M., et al. (2024). The JWST Discovery of the Triply Imaged Type Ia ``Supernova H0pe'' and Observations of the Galaxy Cluster PLCK G165.7+67.0. \apj, 961(2), 171.
• Graaff, A., Rix, H., Carniani, S., Suess, K. A., Charlot, S., Curtis-Lake, E., Arribas, S., Baker, W. M., Boyett, K., Bunker, A. J., Cameron, A. J., Chevallard, J., Curti, M., Eisenstein, D. J., Franx, M., Hainline, K., Hausen, R., Ji, Z., Johnson, B. D., , Jones, G. C., et al. (2024). Ionised gas kinematics and dynamical masses of z \ensuremath{\gtrsim} 6 galaxies from JADES/NIRSpec high-resolution spectroscopy. \aap, 684, A87.
• Hainline, K. N., D'Eugenio, F., Jakobsen, P., Chevallard, J., Carniani, S., Witstok, J., Ji, Z., Curtis-Lake, E., Johnson, B. D., Robertson, B., Tacchella, S., Curti, M., Charlot, S., Helton, J. M., Arribas, S., Bhatawdekar, R., Bunker, A. J., Cameron, A. J., Egami, E., , Eisenstein, D. J., et al. (2024). Searching for Emission Lines at z > 11: The Role of Damped Ly\ensuremath{\alpha} and Hints About the Escape of Ionizing Photons. \apj, 976(2), 160.
• Hainline, K. N., D'Eugenio, F., Sun, F., Helton, J. M., Miles, B. E., Marley, M. S., Lew, B. W., Leisenring, J. M., Bunker, A. J., Cargile, P. A., Carniani, S., Eisenstein, D. J., Juod{\v{z}balis}, I., Johnson, B. D., Robertson, B., Tacchella, S., Williams, C. C., & Willmer, C. N. (2024). JADES: Spectroscopic Confirmation and Proper Motion for a T-Dwarf at 2 kpc. \apj, 975(1), 31.
• Hainline, K. N., Helton, J. M., Johnson, B. D., Sun, F., Topping, M. W., Leisenring, J. M., Baker, W. M., Eisenstein, D. J., Hausen, R., Hviding, R. E., Lyu, J., Robertson, B., Tacchella, S., Williams, C. C., Willmer, C. N., & Roellig, T. L. (2024). Brown Dwarf Candidates in the JADES and CEERS Extragalactic Surveys. \apj, 964(1), 66.
• Hainline, K. N., Johnson, B. D., Robertson, B., Tacchella, S., Helton, J. M., Sun, F., Eisenstein, D. J., Simmonds, C., Topping, M. W., Whitler, L., Willmer, C. N., Rieke, M., Suess, K. A., Hviding, R. E., Cameron, A. J., Alberts, S., Baker, W. M., Baum, S., Bhatawdekar, R., , Bonaventura, N., et al. (2024). The Cosmos in Its Infancy: JADES Galaxy Candidates at z > 8 in GOODS-S and GOODS-N. \apj, 964(1), 71.
• Hainline, K., Jakobsen, P., Chevallard, J., Carniani, S., Witstok, J., Ji, Z., Curtis-Lake, E., Johnson, B., Robertson, B., Tacchella, S., Curti, M., Charlot, S., Helton, J., Arribas, S., Bhatawdekar, R., Bunker, A., Cameron, A., Egami, E., Eisenstein, D., , Hausen, R., et al. (2024). Searching for Emission Lines at z > 11: The Role of Damped Lyα and Hints About the Escape of Ionizing Photons. Astrophysical Journal, 976(2). doi:10.3847/1538-4357/ad8447
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  We describe new ultradeep James Webb Space Telescope (JWST) NIRSpec PRISM and grating spectra for the galaxies JADES-GS-z11-0 ( z spec = 11.122 − 0.003 + 0.005 ) and JADES-GS-z13-0 ( z spec = 13.20 − 0.04 + 0.03 ), the most distant spectroscopically confirmed galaxy discovered in the first year of JWST observations. The extraordinary depth of these observations (75 hr and 56 hr, respectively) provides a unique opportunity to explore the redshifts, stellar properties, UV magnitudes, and slopes for these two sources. For JADES-GS-z11-0, we find evidence for multiple emission lines, including [O ii]λ λ3726, 3729 and [Ne iii]λ3869, resulting in a spectroscopic redshift we determine with 94% confidence. We present stringent upper limits on the emission-line fluxes and line equivalent widths for JADES-GS-z13-0. At this spectroscopic redshift, the Lyα break in JADES-GS-z11-0 can be fit with a damped Lyα absorber with log ( N HI / cm − 2 ) = 22.42 − 0.120 + 0.093 . These results demonstrate how neutral hydrogen fraction and Lyman-damping wings may impact the recovery of spectroscopic redshifts for sources like these, providing insight into the overprediction of the photometric redshifts seen for distant galaxies observed with JWST. In addition, we analyze updated NIRCam photometry to calculate the morphological properties of these resolved sources, and find a secondary source 0.″3 south of JADES-GS-z11-0 at a similar photometric redshift, hinting at how galaxies grow through interactions in the early Universe.
• Hainline, K., Sun, F., Helton, J., Miles, B., Marley, M., Lew, B., Leisenring, J., Bunker, A., Cargile, P., Carniani, S., Eisenstein, D., Johnson, B., Robertson, B., Tacchella, S., Williams, C., Willmer, C., D’Eugenio, F., & Juodžbalis, I. (2024). JADES: Spectroscopic Confirmation and Proper Motion for a T-Dwarf at 2 kpc. Astrophysical Journal, 975(1). doi:10.3847/1538-4357/ad76a7
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  Large area observations of extragalactic deep fields with the James Webb Space Telescope (JWST) have provided a wealth of candidate low-mass L- and T-class brown dwarfs. The existence of these sources, which are at derived distances of hundreds of parsecs to several kiloparsecs from the Sun, has strong implications for the low-mass end of the stellar initial mass function, and the link between stars and planets at low metallicities. In this letter, we present a JWST/NIRSpec PRISM spectrum of brown dwarf JADES-GS-BD-9, confirming its photometric selection from observations taken as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. Fits to this spectrum indicate that the brown dwarf has an effective temperature of 800-900 K (T5-T6) at a distance of 1.8-2.3 kpc from the Sun, with evidence of the source being at low metallicity ([M/H] ≤ −0.5). Finally, because of the cadence of JADES NIRCam observations of this source, we additionally uncover a proper motion between the 2022 and 2023 centroids, and we measure a proper motion of 20 ± 4 mas yr−1 (a transverse velocity of 214 km s−1 at 2.25 kpc). At this predicted metallicity, distance, and transverse velocity, it is likely that this source belongs either to the edge of the Milky Way thick disk or the galactic halo. This spectral confirmation demonstrates the efficacy of photometric selection of these important sources across deep extragalactic JWST imaging.
• Helton, J. M., Sun, F., Woodrum, C., Hainline, K. N., Willmer, C. N., Rieke, G. H., Rieke, M. J., Tacchella, S., Robertson, B., Johnson, B. D., Alberts, S., Eisenstein, D. J., Hausen, R., Bonaventura, N. R., Bunker, A., Charlot, S., Curti, M., Curtis-Lake, E., Looser, T. J., , Maiolino, R., et al. (2024). The JWST Advanced Deep Extragalactic Survey: Discovery of an Extreme Galaxy Overdensity at z = 5.4 with JWST/NIRCam in GOODS-S. \apj, 962(2), 124.
• Helton, J. M., Sun, F., Woodrum, C., Hainline, K. N., Willmer, C. N., Rieke, M. J., Rieke, G. H., Alberts, S., Eisenstein, D. J., Tacchella, S., Robertson, B., Johnson, B. D., Baker, W. M., Bhatawdekar, R., Bunker, A. J., Chen, Z., Egami, E., Ji, Z., Maiolino, R., , Willott, C., et al. (2024). Identification of High-redshift Galaxy Overdensities in GOODS-N and GOODS-S. \apj, 974(1), 41.
• Helton, J., Sun, F., Woodrum, C., Hainline, K., Willmer, C., Rieke, M., Rieke, G., Alberts, S., Eisenstein, D., Tacchella, S., Robertson, B., Johnson, B., Baker, W., Bhatawdekar, R., Bunker, A., Chen, Z., Egami, E., Ji, Z., Maiolino, R., , Willott, C., et al. (2024). Identification of High-redshift Galaxy Overdensities in GOODS-N and GOODS-S. Astrophysical Journal, 974(1). doi:10.3847/1538-4357/ad6867
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  We conduct a systematic search for high-redshift galaxy overdensities at 4.9 < z spec < 8.9 in both the Great Observatories Origins Deep Survey (GOODS)-N and GOODS-S fields using James Webb Space Telescope/Near-Infrared Camera (JWST/NIRCam) imaging from the JWST Advanced Deep Extragalactic Survey and JWST Extragalactic Medium-band Survey in addition to JWST/NIRCam wide field slitless spectroscopy from the First Reionization Epoch Spectroscopic Complete Survey. High-redshift galaxy candidates are identified using Hubble Space Telescope + JWST photometry spanning λ = 0.4-5.0 μm. We confirmed the redshifts for roughly a third of these galaxies using JWST spectroscopy over λ = 3.9-5.0 μm through identification of either Hα or OIII λ 5008 around the best-fit photometric redshift. The rest-ultraviolet magnitudes and continuum slopes of these galaxies were inferred from the photometry: the brightest and reddest objects appear in more dense environments and thus are surrounded by more galaxy neighbors than their fainter and bluer counterparts, suggesting accelerated galaxy evolution within overdense environments. We find 17 significant (δ gal ≥ 3.04, N gal ≥ 4) galaxy overdensities across both fields (seven in GOODS-N and 10 in GOODS-S), including the two highest redshift spectroscopically confirmed galaxy overdensities to date at z spec = 7.954 and z spec = 8.222 (representing densities around ∼6 and ∼12 times that of a random volume). We estimate the total halo mass of these large-scale structures to be 11.5 ≤ log 10 M halo / M ⊙ ≤ 13.4 using an empirical stellar mass-to-halo mass relation, which are likely underestimates as a result of incompleteness. These protocluster candidates are expected to evolve into massive galaxy clusters with log 10 M halo / M ⊙ ≳ 14 by z = 0.
• Jansen, R., Grogin, N., Cohen, S., Smith, B., Silver, R., Maksym, W., Windhorst, R., Carleton, T., Koekemoer, A., Hathi, N., Willmer, C., Frye, B., Alpaslan, M., Ashby, M., Ashcraft, T., Bonoli, S., Brisken, W., Cappelluti, N., Civano, F., , Conselice, C., et al. (2024). TREASUREHUNT: Transients and Variability Discovered with HST in the JWST North Ecliptic Pole Time-domain Field. Astrophysical Journal, Supplement Series, 272(1). doi:10.3847/1538-4365/ad3948
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  The James Webb Space Telescope (JWST) North Ecliptic Pole (NEP) Time-domain Field (TDF) is a >14′ diameter field optimized for multiwavelength time-domain science with JWST. It has been observed across the electromagnetic spectrum both from the ground and from space, including with the Hubble Space Telescope (HST). As part of HST observations over three cycles (the “TREASUREHUNT” program), deep images were obtained with the Wide Field Camera on the Advanced Camera for Surveys in F435W and F606W that cover almost the entire JWST NEP TDF. Many of the individual pointings of these programs partially overlap, allowing an initial assessment of the potential of this field for time-domain science with HST and JWST. The cumulative area of overlapping pointings is ∼88 arcmin2, with time intervals between individual epochs that range between 1 day and 4+ yr. To a depth of m AB ≃ 29.5 mag (F606W), we present the discovery of 12 transients and 190 variable candidates. For the variable candidates, we demonstrate that Gaussian statistics are applicable and estimate that ∼80 are false positives. The majority of the transients will be supernovae, although at least two are likely quasars. Most variable candidates are active galactic nuclei (AGNs), where we find 0.42% of the general z ≲ 6 field galaxy population to vary at the ∼3σ level. Based on a 5 yr time frame, this translates into a random supernova areal density of up to ∼0.07 transients arcmin−2 (∼245 deg−2) per epoch and a variable AGN areal density of ∼1.25 variables arcmin−2 (∼4500 deg−2) to these depths.
• Ji, Z., Williams, C. C., Tacchella, S., Suess, K. A., Baker, W. M., Alberts, S., Bunker, A. J., Johnson, B. D., Robertson, B., Sun, F., Eisenstein, D. J., Rieke, M., Maseda, M. V., Hainline, K., Hausen, R., Rieke, G., Willmer, C. N., Egami, E., Shivaei, I., , Carniani, S., et al. (2024). JADES + JEMS: A Detailed Look at the Buildup of Central Stellar Cores and Suppression of Star Formation in Galaxies at Redshifts 3 < z < 4.5. \apj, 974(1), 135.
• Ji, Z., Williams, C., Tacchella, S., Suess, K., Baker, W., Alberts, S., Bunker, A., Johnson, B., Robertson, B., Sun, F., Eisenstein, D., Rieke, M., Maseda, M., Hainline, K., Hausen, R., Rieke, G., Willmer, C., Egami, E., Shivaei, I., , Carniani, S., et al. (2024). JADES + JEMS: A Detailed Look at the Buildup of Central Stellar Cores and Suppression of Star Formation in Galaxies at Redshifts 3 < z < 4.5. Astrophysical Journal, 974(1). doi:10.3847/1538-4357/ad6e7f
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  We present a spatially resolved study of stellar populations in six galaxies with stellar masses M * ∼ 1010 M ☉ at z ∼ 3.7 using 14-filter James Webb Space Telescope (JWST)/NIRCam imaging from the JADES and JEMS surveys. The six galaxies are visually selected to have clumpy substructures with distinct colors over rest frame 3600−4100 Å, including a red, dominant stellar core that is close to their stellar-light centroids. With 23-filter photometry from the Hubble Space Telescope to JWST, we measure the stellar-population properties of individual structural components via spectral energy distribution fitting using Prospector. We find that the central stellar cores are ≳2 times more massive than the Toomre mass, indicating they may not form via single in situ fragmentation. The stellar cores have stellar ages of 0.4−0.7 Gyr that are similar to the timescale of clump inward migration due to dynamical friction, suggesting that they likely instead formed through the coalescence of giant stellar clumps. While they have not yet quenched, the six galaxies are below the star-forming main sequence by 0.2−0.7 dex. Within each galaxy, we find that the specific star formation rate is lower in the central stellar core, and the stellar-mass surface density of the core is already similar to quenched galaxies of the same masses and redshifts. Meanwhile, the stellar ages of the cores are either comparable to or younger than the extended, smooth parts of the galaxies. Our findings are consistent with model predictions of the gas-rich compaction scenario for the buildup of galaxies’ central regions at high redshifts. We are likely witnessing the coeval formation of dense central cores, along with the onset of galaxy-wide quenching at z > 3.
• Kamieneski, P. S., Frye, B. L., Windhorst, R. A., Harrington, K. C., Yun, M. S., Noble, A., Pascale, M., Foo, N., Cohen, S. H., Jansen, R. A., Carleton, T., Koekemoer, A. M., Willmer, C. N., Summers, J. S., Garuda, N., Leimbach, R., Holwerda, B. W., Pierel, J. D., Jim{\'enez-Andrade}, E. F., , Willner, S., et al. (2024). Birds of a Feather: Resolving Stellar Mass Assembly with JWST/NIRCam in a Pair of Kindred z \ensuremath{\sim} 2 Dusty Star-forming Galaxies Lensed by the PLCK G165.7+67.0 Cluster. \apj, 973(1), 25.
• Kamieneski, P., Frye, B., Windhorst, R., Harrington, K., Yun, M., Noble, A., Pascale, M., Foo, N., Cohen, S., Jansen, R., Carleton, T., Koekemoer, A., Willmer, C., Summers, J., Garuda, N., Leimbach, R., Holwerda, B., Pierel, J., Willner, S., , Alcalde Pampliega, B., et al. (2024). Birds of a Feather: Resolving Stellar Mass Assembly with JWST/NIRCam in a Pair of Kindred z ∼ 2 Dusty Star-forming Galaxies Lensed by the PLCK G165.7+67.0 Cluster. Astrophysical Journal, 973(1). doi:10.3847/1538-4357/ad5d59
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  We present a new parametric lens model for the G165.7+67.0 galaxy cluster, which was discovered with Planck through its bright submillimeter flux, originating from a pair of extraordinary dusty star-forming galaxies (DSFGs) at z ≈ 2.2. Using JWST and interferometric mm/radio observations, we characterize the intrinsic physical properties of the DSFGs, which are separated by only ∼1″ (8 kpc) and a velocity difference ΔV ≲ 600 km s−1 in the source plane, and thus are likely undergoing a major merger. Boasting intrinsic star formation rates SFRIR = 320 ± 70 and 400 ± 80 M ⊙ yr−1, stellar masses of log [ M ⋆ / M ⊙ ] = 10.2 ± 0.1 and 10.3 ± 0.1, and dust attenuations of A V = 1.5 ± 0.3 and 1.2 ± 0.3, they are remarkably similar objects. We perform spatially resolved pixel-by-pixel spectral energy distribution (SED) fitting using rest-frame near-UV to near-IR imaging from JWST/NIRCam for both galaxies, resolving some stellar structures down to 100 pc scales. Based on their resolved specific star formation rates (SFRs) and UVJ colors, both DSFGs are experiencing significant galaxy-scale star formation events. If they are indeed interacting gravitationally, this strong starburst could be the hallmark of gas that has been disrupted by an initial close passage. In contrast, the host galaxy of SN H0pe has a much lower SFR than the DSFGs, and we present evidence for the onset of inside-out quenching and large column densities of dust even in regions of low specific SFR. Based on the intrinsic SFRs of the DSFGs inferred from UV through far-infrared SED modeling, this pair of objects alone is predicted to yield an observable 1.1 ± 0.2 core-collapse supernovae per year, making this cluster field ripe for continued monitoring.
• Lyu, J., Alberts, S., Rieke, G. H., Shivaei, I., P{\'erez-Gonz\'alez}, P. G., Sun, F., Hainline, K. N., Baum, S., Bonaventura, N., Bunker, A. J., Egami, E., Eisenstein, D. J., Florian, M., Ji, Z., Johnson, B. D., Morrison, J., Rieke, M., Robertson, B., Rujopakarn, W., , Tacchella, S., et al. (2024). Active Galactic Nuclei Selection and Demographics: A New Age with JWST/MIRI. \apj, 966(2), 229.
• Lyu, J., Alberts, S., Rieke, G., Shivaei, I., Sun, F., Hainline, K., Baum, S., Bonaventura, N., Bunker, A., Egami, E., Eisenstein, D., Florian, M., Ji, Z., Johnson, B., Morrison, J., Rieke, M., Robertson, B., Rujopakarn, W., Tacchella, S., , Scholtz, J., et al. (2024). Active Galactic Nuclei Selection and Demographics: A New Age with JWST/MIRI. Astrophysical Journal, 966(2). doi:10.3847/1538-4357/ad3643
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  Understanding the coevolution of supermassive black holes and their host systems requires a comprehensive census of active galactic nuclei (AGNs) behavior across a wide range of redshift, luminosity, obscuration level, and galaxy properties. We report significant progress with JWST toward this goal from the Systematic Mid-infrared Instrument Legacy Extragalactic Survey (SMILES). Based on comprehensive spectral energy distribution (SED) analysis of 3273 MIRI-detected sources, we identify 217 AGN candidates over a survey area of ∼34 arcmin2, including a primary sample of 111 AGNs in normal massive galaxies (M * > 109.5 M ☉) at z ∼ 0-4, an extended sample of 86 AGN candidates in low-mass galaxies (M * < 109.5 M ☉), and a high-z sample of 20 AGN candidates at z ∼ 4-8.4. Notably, about 80% of our MIRI-selected AGN candidates are new discoveries despite the extensive pre-JWST AGN searches. Even among the massive galaxies where the previous AGN search is believed to be thorough, 34% of the MIRI AGN identifications are new, highlighting the impact of obscuration on previous selections. By combining our results with the efforts at other wavelengths, we build the most complete AGN sample to date and examine the relative performance of different selection techniques. We find the obscured AGN fraction increases from L AGN,bol ∼ 1010 L ⊙ to 1011 L ⊙ and then drops toward higher luminosity. Additionally, the obscured AGN fraction gradually increases from z ∼ 0 to z ∼ 4 with most high-z AGNs obscured. We discuss how AGN obscuration, intrinsic SED variations, galaxy contamination, survey depth, and selection techniques complicate the construction of a complete AGN sample.
• Ma, Z., Sun, B., Cheng, C., Yan, H., Ling, C., Sun, F., Foo, N., Egami, E., Diego, J. M., Cohen, S. H., Jansen, R. A., Summers, J., Windhorst, R. A., D'Silva, J. C., Koekemoer, A. M., Coe, D., Conselice, C. J., Driver, S. P., Frye, B., , Grogin, N. A., et al. (2024). JWST View of Four Infant Galaxies at z = 8.31\textendash8.49 in the MACS J0416.1???2403 Field and Implications for Reionization. \apj, 975(1), 87.
• Ma, Z., Sun, B., Cheng, C., Yan, H., Ling, C., Sun, F., Foo, N., Egami, E., Diego, J., Cohen, S., Jansen, R., Summers, J., Windhorst, R., Koekemoer, A., Coe, D., Conselice, C., Driver, S., Frye, B., Grogin, N., , Marshall, M., et al. (2024). JWST View of Four Infant Galaxies at z = 8.31-8.49 in the MACS J0416.1−2403 Field and Implications for Reionization. Astrophysical Journal, 975(1). doi:10.3847/1538-4357/ad7b32
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  New JWST/NIRCam wide-field slitless spectroscopy provides redshifts for four z > 8 galaxies located behind the lensing cluster MACS J0416.1−2403. Two of them, “Y1” and “JD,” have previously reported spectroscopic redshifts based on Atacama Large Millimeter/submillimeter Array measurements of [O iii] 88 μm and/or [C ii] 157.7 μm lines. Y1 is a merging system of three components, and the existing redshift z = 8.31 is confirmed. However, JD is at z = 8.34 instead of the previously claimed z = 9.28. JD’s close companion, “JD-N,” which was a previously discovered z > 8 candidate, is now identified at the same redshift as JD. JD and JD-N form an interacting pair. A new candidate at z > 8, “f090d_018,” is also confirmed and is at z = 8.49. These four objects are likely part of an overdensity that signposts a large structure extending ∼165 kpc in projected distance and ∼48.7 Mpc in radial distance. They are magnified by less than 1 mag and have an intrinsic M UV ranging from −19.57 to −20.83 mag. Their spectral energy distributions show that the galaxies are all very young with ages ∼ 4-18 Myr and stellar masses of about 107-8 M ⊙. These infant galaxies have very different star formation rates ranging from a few to over a hundred solar masses per year, but only two of them (JD and f090d_018) have blue rest-frame UV slopes β < −2.0 indicative of a high Lyman-continuum photon escape fraction that could contribute significantly to the cosmic hydrogen-reionizing background. Interestingly, these two galaxies are the least massive and least active ones among the four. The other two systems have much flatter UV slopes largely because of their high dust extinction (A V = 0.9-1.0 mag). Their much lower indicated escape fractions show that even very young, actively star-forming galaxies can have a negligible contribution to reionization when they quickly form dust throughout their bodies.
• Ma, Z., Yan, H., Sun, B., Cohen, S. H., Jansen, R. A., Summers, J., Windhorst, R. A., D'Silva, J. C., Koekemoer, A. M., Coe, D., Conselice, C. J., Driver, S. P., Frye, B., Grogin, N. A., Marshall, M. A., Nonino, M., Ortiz, R., Pirzkal, N., Robotham, A., , Ryan, R. E., et al. (2024). JWST's PEARLS: Improved Flux Calibration for NIRCam. \pasp, 136(2), 024501.
• Maiolino, R., Carniani, S., Chevallard, J., Curtis-Lake, E., Witstok, J., Charlot, S., Baker, W., Arribas, S., Boyett, K., Bunker, A., Curti, M., Eisenstein, D., Hainline, K., Ji, Z., Johnson, B., Kumari, N., Looser, T., Nakajima, K., Nelson, E., , Rieke, M., et al. (2024). JADES: Carbon enrichment 350 Myr after the Big Bang. Astronomy and Astrophysics, 689. doi:10.1051/0004-6361/202348636
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  Finding the emergence of the first metals in the early Universe and identifying their origin are some of the most important goals of modern astrophysics. We present deep JWST/NIRSpec spectroscopy of GS-z12, a galaxy at z = 12.5, in which we report the detection of the C iii]λλ1907,1909 nebular emission line. This represents the most distant detection of a metal transition, and the most distant redshift determination based on emission lines. In addition, we report tentative detections of [O ii]λλ3726,3729 and [Ne iii]λ3869, and possibly O iii]λλ1661,1666. By using the accurate redshift obtained from C iii], we can model the Lyα drop to reliably measure an absorbing column density of hydrogen of NHi ≈ 1022 cm−2, which is too high for an IGM origin and implies an abundant neutral ISM in GS-z12 or in the CGM around it. We tentatively infer a lower limit for the neutral gas mass of about 107 M which, compared with the galaxy stellar mass of ∼5 × 107 M , implies a gas fraction higher than about 0.2–0.5. By comparing the measured emission lines with model-based diagnostic diagrams, we derive a solar or even super-solar carbon-to-oxygen ratio, tentatively log (C/O) > −0.21 dex ([C/O] > 0.15 dex), while a Bayesian modelling of the spectrum indicates log (C/O) = −0.30 ± 0.07 dex ([C/O] = 0.06 ± 0.07 dex). This is higher than the C/O measured in galaxies discovered by JWST at z = 6−9, and higher than the C/O arising from Type II supernovae enrichment. Asymptotic giant branch stars can hardly contribute to the observed carbon enrichment at these early epochs and low metallicities. Such a high C/O in a galaxy observed 350 Myr after the Big Bang may thus be explained by the yields of extremely metal-poor stars, and may even be the heritage of the first generation of supernovae from Population III progenitors. A robust determination of the total metallicity in this galaxy is essential to constrain these scenarios.
• Maiolino, R., Perna, M., Scholtz, J., Witten, C., Laporte, N., Witstok, J., Carniani, S., Tacchella, S., Baker, W., Arribas, S., Nakajima, K., Eisenstein, D., Bunker, A., Charlot, S., Cresci, G., Curti, M., Curtis-Lake, E., de Graaff, A., Egami, E., , Ji, Z., et al. (2024). JADES Possible Population III signatures at z = 10.6 in the halo of GN-z11. Astronomy and Astrophysics, 687(Issue). doi:10.1051/0004-6361/202347087
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  Finding the first generation of stars formed out of pristine gas in the early Universe, known as Population III (PopIII) stars, is one of the most important goals of modern astrophysics. Recent models have suggested that PopIII stars may form in pockets of pristine gas in the halo of more evolved galaxies. We present NIRSpec integral field spectroscopy and micro-shutter array spectroscopic observations of the region around GNz11, an exceptionally luminous galaxy at z = 10.6, that reveal a greater than 5σ detection of a feature consistent with being HeIIλ1640 emission at the redshift of GN-z11. The very high equivalent width of the putative HeII emission in this clump (log (EWrest(HeII)/Å) = 1.79+−001525) and a lack of metal lines can be explained in terms of photoionisation by PopIII stars, while photoionisation by PopII stars is inconsistent with the data. The high equivalent width would also indicate that the putative PopIII stars likely have an initial mass function with an upper cutoff reaching at least 500 M . The PopIII bolometric luminosity inferred from the HeII line would be ∼7 × 109 L , which would imply a total stellar mass formed in the burst of ∼2 × 105 M . We find that photoionisation by the active galactic nucleus (AGN) in GN-z11 cannot account for the HeII luminosity observed in the clump but can potentially be responsible for an additional HeII emission observed closer to GN-z11. We also consider the possibility of in situ photoionisation by an accreting direct collapse black hole hosted by the HeII clump. We find that this scenario is less favoured, but it remains a possible alternative interpretation. We also report the detection of a Lyα halo stemming out of GN-z11 and extending out to ∼2 kpc as well as resolved funnel-shaped CIII emission likely tracing the ionisation cone of the AGN.
• Maiolino, R., Scholtz, J., Witstok, J., Carniani, S., D'Eugenio, F., Graaff, A., {\"Ubler}, H., Tacchella, S., Curtis-Lake, E., Arribas, S., Bunker, A., Charlot, S., Chevallard, J., Curti, M., Looser, T. J., Maseda, M. V., Rawle, T. D., Pino}, B., Willott, C. J., , Egami, E., et al. (2024). A small and vigorous black hole in the early Universe. \nat, 627(8002), 59-63.
• Maiolino, R., Scholtz, J., Witstok, J., Carniani, S., D'Eugenio, F., Graaff, A., {\"Ubler}, H., Tacchella, S., Curtis-Lake, E., Arribas, S., Bunker, A., Charlot, S., Chevallard, J., Curti, M., Looser, T. J., Maseda, M. V., Rawle, T. D., Pino}, B., Willott, C. J., , Egami, E., et al. (2024). Author Correction: A small and vigorous black hole in the early Universe. \nat, 630(8015), E2-E2.
• Maiolino, R., Scholtz, J., Witstok, J., Carniani, S., de Graaff, A., Tacchella, S., Curtis-Lake, E., Arribas, S., Bunker, A., Charlot, S., Chevallard, J., Curti, M., Looser, T., Maseda, M., Rawle, T., Willott, C., Egami, E., Eisenstein, D., Hainline, K., , Robertson, B., et al. (2024). Author Correction: A small and vigorous black hole in the early Universe(Nature, 10.1038/s41586-024-07052-5). Nature, 630(8015). doi:10.1038/s41586-024-07494-x
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  Correction to: Naturehttps://doi.org/10.1038/s41586-024-07052-5 Published online 17 January 2024 In the version of the article initially published, the coloured lines in Fig. 1b were incorrect and did not show the fit to the data. The original and corrected panel can be seen below in Fig. 1. In addition, the dotted line in panel d representing the most extreme case of low-metallicity, young star-forming galaxy should have been orange, not black. The errors have been corrected in the HTML and PDF versions of the article. (Figure presented.).
• Maiolino, R., {\"Ubler}, H., Perna, M., Scholtz, J., D'Eugenio, F., Witten, C., Laporte, N., Witstok, J., Carniani, S., Tacchella, S., Baker, W. M., Arribas, S., Nakajima, K., Eisenstein, D. J., Bunker, A. J., Charlot, S., Cresci, G., Curti, M., Curtis-Lake, E., , Graaff, A., et al. (2024). JADES. Possible Population III signatures at z = 10.6 in the halo of GN-z11. \aap, 687, A67.
• Nabizadeh, A., Zackrisson, E., Pacucci, F., Maksym, W., Li, W., Civano, F., Cohen, S., Koekemoer, A., Summers, J., Windhorst, R., Adams, N., Conselice, C., Coe, D., Driver, S., Frye, B., Grogin, N., Jansen, R., Marshall, M., Nonino, M., , Pirzkal, N., et al. (2024). A search for high-redshift direct-collapse black hole candidates in the PEARLS north ecliptic pole field. Astronomy and Astrophysics, 683(Issue). doi:10.1051/0004-6361/202347724
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  Direct-collapse black holes (DCBHs) of mass ∼104−105 M that form in HI-cooling halos in the early Universe are promising progenitors of the &109 M supermassive black holes that fuel observed z & 7 quasars. Efficient accretion of the surrounding gas onto such DCBH seeds may render them sufficiently bright for detection with the JWST up to z ≈ 20. Additionally, the very steep and red spectral slope predicted across the ≈1−5 µm wavelength range of the JWST/NIRSpec instrument during their initial growth phase should make them photometrically identifiable up to very high redshifts. In this work, we present a search for such DCBH candidates across the 34 arcmin2 in the first two spokes of the JWST cycle-1 PEARLS survey of the north ecliptic pole time-domain field covering eight NIRCam filters down to a maximum depth of ∼29 AB mag. We identify two objects with spectral energy distributions consistent with theoretical DCBH models. However, we also note that even with data in eight NIRCam filters, objects of this type remain degenerate with dusty galaxies and obscured active galactic nuclei over a wide range of redshifts. Follow-up spectroscopy would be required to pin down the nature of these objects. Based on our sample of DCBH candidates and assumptions on the typical duration of the DCBH steep-slope state, we set a conservative upper limit of .5 × 10−4 comoving Mpc−3 (cMpc−3) on the comoving density of host halos capable of hosting DCBHs with spectral energy distributions similar to the theoretical models at z ≈ 6−14.
• Nabizadeh, A., Zackrisson, E., Pacucci, F., Peter, M. W., Li, W., Civano, F., Cohen, S. H., D'Silva, J. C., Koekemoer, A. M., Summers, J., Windhorst, R. A., Adams, N., Conselice, C. J., Coe, D., Driver, S. P., Frye, B., Grogin, N. A., Jansen, R. A., Marshall, M. A., , Nonino, M., et al. (2024). A search for high-redshift direct-collapse black hole candidates in the PEARLS north ecliptic pole field. \aap, 683, A58.
• O'Brien, R., Jansen, R. A., Grogin, N. A., Cohen, S. H., Smith, B. M., Silver, R. M., Maksym, W., Windhorst, R. A., Carleton, T., Koekemoer, A. M., Hathi, N. P., Willmer, C. N., Frye, B. L., Alpaslan, M., Ashby, M., Ashcraft, T., Bonoli, S., Brisken, W., Cappelluti, N., , Civano, F., et al. (2024). TREASUREHUNT: Transients and Variability Discovered with HST in the JWST North Ecliptic Pole Time-domain Field. \apjs, 272(1), 19.
• Ortiz, R., Windhorst, R. A., Cohen, S. H., Willner, S. P., Jansen, R. A., Carleton, T., Kamieneski, P. S., Rutkowski, M. J., Smith, B. M., Summers, J., Cheng, C., Coe, D., Conselice, C. J., Diego, J. M., Driver, S. P., D'Silva, J. C., Frye, B. L., Gim, H. B., Grogin, N. A., , Hammel, H. B., et al. (2024). PEARLS: Discovery of Point-source Features within Galaxies in the North Ecliptic Pole Time Domain Field. \apj, 974(2), 258.
• Ortiz, R., Windhorst, R., Cohen, S., Willner, S., Jansen, R., Carleton, T., Kamieneski, P., Rutkowski, M., Smith, B., Summers, J., Cheng, C., Coe, D., Conselice, C., Diego, J., Driver, S., Frye, B., Gim, H., Grogin, N., Hammel, H., , Hathi, N., et al. (2024). PEARLS: Discovery of Point-source Features within Galaxies in the North Ecliptic Pole Time Domain Field. Astrophysical Journal, 974(2). doi:10.3847/1538-4357/ad6d5e
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  The first public 0.9-4.4 μm NIRCam images of the North Ecliptic Pole Time Domain Field uncovered galaxies displaying point-source features in their cores as seen in the longer-wavelength filters. We visually identified a sample of 66 galaxies (∼1 galaxy arcmin-2) with pointlike cores and have modeled their two-dimensional light profiles with GalFit, identifying 16 galactic nuclei with measurable point-source components. GalFit suggests that the visual sample is a mix of both compact stellar bulge and point-source galaxy cores. This core classification is complemented by spectral energy distribution modeling to infer the sample’s active galactic nucleus (AGN) and host-galaxy parameters. For galaxies with measurable point-source components, the median fractional AGN contribution to their 0.1-30.0 μm flux is 0.44, and 14/16 are color-classified AGN. We conclude that near-infrared point-source galaxy cores are signatures of AGN. In addition, we define an automated sample-selection criterion to identify these point-source features. This criterion can be used in other extant and future NIRCam images to streamline the search for galaxies with unresolved IR-luminous AGN. The James Webb Space Telescope’s superb angular resolution and sensitivity at infrared wavelengths are resurrecting the morphological identification of AGN.
• Pierel, J., Frye, B., Pascale, M., Caminha, G., Chen, W., Dhawan, S., Gilman, D., Grayling, M., Huber, S., Kelly, P., Thorp, S., Arendse, N., Birrer, S., Bronikowski, M., Ca{\~nameras}, R., Coe, D., Cohen, S., Conselice, C., Driver, S., , D{\'Silva}, J., et al. (2024). JWST Photometric Time-delay and Magnification Measurements for the Triply Imaged Type Ia ``SN H0pe'' at z = 1.78. \apj, 967(1), 50.
• Pierel, J., Frye, B., Pascale, M., Caminha, G., Chen, W., Dhawan, S., Gilman, D., Grayling, M., Huber, S., Kelly, P., Thorp, S., Arendse, N., Birrer, S., Bronikowski, M., Coe, D., Cohen, S., Conselice, C., Driver, S., Engesser, M., , Foo, N., et al. (2024). JWST Photometric Time-delay and Magnification Measurements for the Triply Imaged Type Ia “SN H0pe” at z = 1.78. Astrophysical Journal, 967(1). doi:10.3847/1538-4357/ad3c43
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  Supernova (SN) SN H0pe is a gravitationally lensed, triply imaged, Type Ia SN (SN Ia) discovered in James Webb Space Telescope imaging of the PLCK G165.7+67.0 cluster of galaxies. Well-observed multiply imaged SNe provide a rare opportunity to constrain the Hubble constant (H 0), by measuring the relative time delay between the images and modeling the foreground mass distribution. SN H0pe is located at z = 1.783 and is the first SN Ia with sufficient light-curve sampling and long enough time delays for an H 0 inference. Here we present photometric time-delay measurements and SN properties of SN H0pe. Using JWST/NIRCam photometry, we measure time delays of Δt ab = − 116.6 − 9.3 + 10.8 observer-frame days and Δt cb = − 48.6 − 4.0 + 3.6 observer-frame days relative to the last image to arrive (image 2b; all uncertainties are 1σ), which corresponds to a ∼5.6% uncertainty contribution for H 0 assuming 70 km s−1 Mpc−1. We also constrain the absolute magnification of each image to μ a = 4.3 − 1.8 + 1.6 , μ b = 7.6 − 2.6 + 3.6 , μ c = 6.4 − 1.5 + 1.6 by comparing the observed peak near-IR magnitude of SN H0pe to the nonlensed population of SNe Ia.
• Polletta, M., Frye, B., Garuda, N., Willner, S., Berta, S., Kneissl, R., Dole, H., Jansen, R., Lehnert, M., Cohen, S., Summers, J., Windhorst, R., D'Silva, J., Koekemoer, A., Coe, D., Conselice, C., Driver, S., Grogin, N., Marshall, M., , Nonino, M., et al. (2024). JWST's PEARLS: Resolved study of the stellar and dust components in starburst galaxies at cosmic noon. Astronomy and Astrophysics, 690(Issue). doi:10.1051/0004-6361/202450671
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  Dusty star-forming galaxies (DSFGs) significantly contribute to the stellar buildup in galaxies during "cosmic noon"the peak epoch of cosmic star formation. Major mergers and gas accretion are often invoked to explain DSFGs'prodigious star formation rates (SFRs) and large stellar masses. We conducted a spatially resolved morphological analysis of the rest-frame ultraviolet/near-infrared (~0.25- 1.3 μm) emission in three DSFGs at z ≃ 2.5. Initially discovered as carbon monoxide (CO) emitters by NOrthern Extended Millimeter Array (NOEMA) observations of a bright (S350 μm = 111 ± 10 mJy) Herschel source, we observed them with the James Webb Space Telescope/NIRCam as part of the PEARLS program. The NIRCam data reveal the galaxies'stellar populations and dust distributions on scales of 250 pc. Spatial variations in stellar mass, SFR, and dust extinction are determined in resolved maps obtained through pixel-based spectral energy distribution fitting. The CO emitters are massive (Mstar ≃ (3 - 30)× 1010 M⊙), dusty starburst galaxies with SFRs ranging from 340 to 2500 M⊙ yr-1, positioning them among the most active star-forming galaxies at 2 < z < 3. Notably, they belong to the ~1.5% of the entire JWST population with extremely red colors. Their morphologies are disk like (Sérsic index n ≃ 1), with effective radii of 2.0- 4.4 kpc, and exhibit substructures such as clumps and spiral arms. The galaxies have dust extinctions up to AV = 5- 7 mag extending over several kiloparsecs with asymmetric distributions that include off-center regions resembling bent spiral arms and clumps. The near-infrared dust-attenuation curve in these sources deviates from standard laws, possibly implying different dust- star geometries or dust grain properties than commonly assumed in starburst galaxies. The proximity (< 5) of galaxies with consistent redshifts, strong color gradients, an overall disturbed appearance, asymmetric dust obscuration, and widespread star formation collectively favor interactions (minor mergers and flybys) as the mechanism driving the CO galaxies'exceptional SFRs. The galaxies'large masses and rich environment hint at membership in two proto-structures, as initially inferred from their association with a Planck-selected high-z source.
• Polletta, M., Frye, B., Garuda, N., Willner, S., Berta, S., Kneissl, R., Dole, H., Jansen, R., Lehnert, M., Cohen, S., Summers, J., Windhorst, R., D'Silva, J., Koekemoer, A., Coe, D., Conselice, C., Driver, S., Grogin, N., Marshall, M., , Nonino, M., et al. (2024). JWST's PEARLS: Resolved study of the stellar and dust components in starburst galaxies at cosmic noon. \aap, 690, A285.
• P{\'erez-Gonz\'alez}, P. G., Barro, G., Rieke, G. H., Lyu, J., Rieke, M., Alberts, S., Williams, C. C., Hainline, K., Sun, F., Pusk{\'as}, D., Annunziatella, M., Baker, W. M., Bunker, A. J., Egami, E., Ji, Z., Johnson, B. D., Robertson, B., Rodr{\'\iguez, D., Rujopakarn, W., , Shivaei, I., et al. (2024). What Is the Nature of Little Red Dots and what Is Not, MIRI SMILES Edition. \apj, 968(1), 4.
• Rieke, G., Alberts, S., Shivaei, I., Lyu, J., Willmer, C. N., P{\'erez-Gonz\'alez}, P., & Williams, C. C. (2024). SMILES: A Prototype JWST Multiband Mid-infrared Survey. \apj, 975(1), 83.
• Rieke, G., Alberts, S., Shivaei, I., Lyu, J., Willmer, C., Williams, C., & Pérez-González, P. (2024). SMILES: A Prototype JWST Multiband Mid-infrared Survey. Astrophysical Journal, 975(1). doi:10.3847/1538-4357/ad6cd2
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  The Mid-Infrared Instrument (MIRI) for JWST is supplied with a suite of imaging band-pass filters optimized for full spectral coverage in eight intermediate-width bands from 5 to 26 μm and a narrower one at 11.3 μm. This contrasts with previous infrared space telescopes, which generally have provided only two broad bands, one near 10 μm and the other near 20 μm. The expanded MIRI spectral capability provides new possibilities for detailed interpretation of survey results. This is an important feature of the instrument, on top of its great increase in sensitivity and angular resolution over any previous mission. The Systematic Mid-infrared Instrument Legacy Extragalactic Survey (SMILES) was designed to take full advantage of this capability. This paper briefly describes the history of infrared surveys that paved the way for MIRI on JWST and for our approach to designing SMILES. It illustrates the use of the observations for a broad range of science programs and concludes with a brief summary of the need for additional full multiband surveys with JWST/MIRI. This paper is an overall introduction to the survey and is accompanied by a full data release, described in detail by S. Alberts et al.
• Rieke, G., Schlawin, E., Proffitt, C. R., & Willmer, C. (2024). Absolute Calibration. IV. Use of G-type Stars as Primary Calibrators. \aj, 167(5), 213.
• Robertson, B., Johnson, B. D., Tacchella, S., Eisenstein, D. J., Hainline, K., Arribas, S., Baker, W. M., Bunker, A. J., Carniani, S., Cargile, P. A., Carreira, C., Charlot, S., Chevallard, J., Curti, M., Curtis-Lake, E., D'Eugenio, F., Egami, E., Hausen, R., Helton, J. M., , Jakobsen, P., et al. (2024). Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic Star Formation Rate Density 300 Myr after the Big Bang. \apj, 970(1), 31.
• Robertson, B., Johnson, B., Tacchella, S., Eisenstein, D., Hainline, K., Arribas, S., Baker, W., Bunker, A., Carniani, S., Cargile, P., Carreira, C., Charlot, S., Chevallard, J., Curti, M., Curtis-Lake, E., Egami, E., Hausen, R., Helton, J., Jakobsen, P., , Ji, Z., et al. (2024). Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic Star Formation Rate Density 300 Myr after the Big Bang. Astrophysical Journal, 970(1). doi:10.3847/1538-4357/ad463d
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  We characterize the earliest galaxy population in the JADES Origins Field, the deepest imaging field observed with JWST. We make use of ancillary Hubble Space Telescope optical images (five filters spanning 0.4-0.9 μm) and novel JWST images with 14 filters spanning 0.8−5 μm, including seven medium-band filters, and reaching total exposure times of up to 46 hr per filter. We combine all our data at >2.3 μm to construct an ultradeep image, reaching as deep as ≈31.4 AB mag in the stack and 30.3-31.0 AB mag (5σ, r = 0.″1 circular aperture) in individual filters. We measure photometric redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts z = 11.5−15. These objects show compact half-light radii of R 1/2 ∼ 50−200 pc, stellar masses of M ⋆ ∼ 107−108 M ☉, and star formation rates ∼ 0.1−1 M ☉ yr−1. Our search finds no candidates at 15 < z < 20, placing upper limits at these redshifts. We develop a forward-modeling approach to infer the properties of the evolving luminosity function without binning in redshift or luminosity that marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the impact of nondetections. We find a z = 12 luminosity function in good agreement with prior results, and that the luminosity function normalization and UV luminosity density decline by a factor of ∼2.5 from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical models for evolution of the dark matter halo mass function.
• Saxena, A., Bunker, A. J., Jones, G. C., Stark, D. P., Cameron, A. J., Witstok, J., Arribas, S., Baker, W. M., Baum, S., Bhatawdekar, R., Bowler, R., Boyett, K., Carniani, S., Charlot, S., Chevallard, J., Curti, M., Curtis-Lake, E., Eisenstein, D. J., Endsley, R., , Hainline, K., et al. (2024). JADES: The production and escape of ionizing photons from faint Lyman-alpha emitters in the epoch of reionization. \aap, 684, A84.
• Saxena, A., Bunker, A., Jones, G., Stark, D., Cameron, A., Witstok, J., Arribas, S., Baker, W., Baum, S., Bhatawdekar, R., Bowler, R., Boyett, K., Carniani, S., Charlot, S., Chevallard, J., Curti, M., Curtis-Lake, E., Eisenstein, D., Endsley, R., , Hainline, K., et al. (2024). JADES: The production and escape of ionizing photons from faint Lyman-alpha emitters in the epoch of reionization. Astronomy and Astrophysics, 684(Issue). doi:10.1051/0004-6361/202347132
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  We present the properties of 17 faint Lyman-α emitting galaxies (LAEs) at z > 5.8 from the JWST Advanced Deep Extragalactic Survey (JADES) spectroscopic data in the Hubble Ultra Deep Field/GOODS-S. These LAEs span a redshift range z ≈ 5.8−8.0 and a UV magnitude range MUV ≈ −17 to −20.6, with the Lyα equivalent width (EW) in the range ≈ 25−350 Å. The detection of other rest-optical emission lines in the spectra of these LAEs enables the determination of accurate systemic redshifts and Lyα velocity offsets, as well as the physical and chemical composition of their stars and interstellar media. These faint LAEs are consistent with metal-poor systems with high ionization parameters, similar to the general galaxy population at z > 6. We measured an average ionizing photon production efficiency, log(ξion/erg−1 Hz) ≈ 25.57 across our LAEs, which does not evolve strongly with redshift. We report an anti-correlation between the Lyα escape fraction and the velocity offset from systemic redshift, consistent with model expectations. We further find that the strength and velocity offset of Lyα are neither correlated with galaxy spectroscopic properties nor with ξion. We find a decrease in Lyα escape fractions with redshift, indicative of decreasing sizes of ionized bubbles around LAEs at high redshifts. We used a range of galaxy properties to predict Lyman continuum escape fractions for our LAEs, finding that the ionizing photon output into the intergalactic medium from our LAEs remains roughly constant across the observed Lyα EW, showing a mild increase at fainter UV magnitudes and at higher redshifts. We derived correlations between the ionizing photon output from LAEs and their UV magnitudes, Lyα strengths and redshifts, which can be used to constrain the ionizing photon contribution of LAEs at z > 6 towards cosmic reionization.
• Scholtz, J., Witten, C., Laporte, N., Perna, M., Maiolino, R., Arribas, S., Baker, W., Bennett, J., D'Eugenio, F., Simmonds, C., Tacchella, S., Witstok, J., Bunker, A., Carniani, S., Charlot, S., Cresci, G., Curtis-Lake, E., Eisenstein, D., Kumari, N., , Robertson, B., et al. (2024). GN-z11: The environment of an active galactic nucleus at z= 10.603: New insights into the most distant Ly α detection. Astronomy and Astrophysics, 687. doi:10.1051/0004-6361/202347187
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  Recent observations with the James Webb Space Telescope (JWST) have further refined the spectroscopic redshift of GN-z11, one of the most distant galaxies identified with the Hubble Space Telescope, at za=a10.603. The presence of extremely dense gas (> 1010 cm-3), the detection of high-ionisation lines and of CII∗1335 emission, and the presence of an ionisation cone indicate that GN-z11 also hosts an active galactic nucleus. Further photometric and spectroscopic follow-up demonstrates that it lies in a large-scale, overdense structure with possible signatures of Population III stars in its halo. Surprisingly, Lyα has also been detected despite the expected largely neutral intergalactic medium at such a redshift. We exploit recent JWST/NIRSpec integral field unit observations to demonstrate that the Lyα emission in GN-z11 is part of an extended halo with a minimum size of 0.8-3.2 kpc, depending on the definition used to derive the halo size. The surface brightness of the Lyα halo around GN-z11 appears consistent with Lyα halos observed around za∼6 quasars. At the wavelength of Lyα at za∼10.6, we identify three other emission line candidates within the integral field unit field of view with no UV rest-frame counterpart visible in deep images from the JWST/NIRCam. If confirmed, this could be the first evidence that the local region of GN-z11 represents a candidate protocluster core, forming just 400 Myr after the Big Bang. We give a first estimate of the dark matter halo mass of this structure (Mha-2.96a- 0.39+0.44-1010-), which is consistent with a Coma-like cluster progenitor.
• Scholtz, J., Witten, C., Laporte, N., {\"Ubler}, H., Perna, M., Maiolino, R., Arribas, S., Baker, W. M., Bennett, J. S., D'Eugenio, F., Simmonds, C., Tacchella, S., Witstok, J., Bunker, A. J., Carniani, S., Charlot, S., Cresci, G., Curtis-Lake, E., Eisenstein, D. J., , Kumari, N., et al. (2024). GN-z11: The environment of an active galactic nucleus at z = 10.603. New insights into the most distant Ly\ensuremath{\alpha} detection. \aap, 687, A283.
• Shivaei, I., Alberts, S., Florian, M., Rieke, G., Wuyts, S., Bodansky, S., Bunker, A. J., Cameron, A. J., Curti, M., D'Eugenio, F., Dudzevi{\v{c}i\={u}t\.{e}}, U., Ji, Z., Johnson, B. D., Kramarenko, I., Lyu, J., Matthee, J., Morrison, J., Naidu, R., P{\'erez-Gonz\'alez}, P. G., , Reddy, N., et al. (2024). A new census of dust and polycyclic aromatic hydrocarbons at z = 0.7\textendash2 with JWST MIRI. \aap, 690, A89.
• Shivaei, I., Alberts, S., Florian, M., Rieke, G., Wuyts, S., Bodansky, S., Bunker, A., Cameron, A., Curti, M., Da'eugenio, F., Ji, Z., Johnson, B., Kramarenko, I., Lyu, J., Matthee, J., Morrison, J., Naidu, R., Reddy, N., Robertson, B., , Sun, Y., et al. (2024). A new census of dust and polycyclic aromatic hydrocarbons at z = 0.7-2 with JWST MIRI. Astronomy and Astrophysics, 690(Issue). doi:10.1051/0004-6361/202449579
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  Aims. This paper utilises the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) to extend the observational studies of dust and polycyclic aromatic hydrocarbon (PAH) emission to a new mass and star formation rate (SFR) parameter space beyond our local Universe. The combination of fully sampled spectral energy distributions (SEDs) with multiple mid-infrared (mid-IR) bands and the unprecedented sensitivity of MIRI allows us to investigate dust obscuration and PAH behaviour from z = 0.7 up to z = 2 in typical main-sequence galaxies. Our focus is on constraining the evolution of PAH strength and the dust-obscured luminosity fraction before and during cosmic noon, the epoch of peak star formation activity in the Universe. Methods. In this study, we utilise MIRI multi-band imaging data from the SMILES survey (5 to 25 μm), complemented with NIRCam photometry from the JADES survey (1 to 5 μm), available HST photometry (0.4 to 0.9 μm), and spectroscopic redshifts from the FRESCO and JADES surveys in GOODS-S for 443 star-forming (without dominant active galactic nucleus (AGN)) galaxies at z = 0.7-2.0. This redshift range was chosen to ensure that the MIRI data cover mid-IR dust emission. Our methodology involved employing ultraviolet (UV) to IR energy balance SED fitting to robustly constrain the fraction of dust mass in PAHs and dust-obscured luminosity. Additionally, we inferred dust sizes from MIRI 15 μm imaging data, enhancing our understanding of the physical characteristics of dust within these galaxies. Results. We find a strong correlation between the fraction of dust in PAHs (PAH fraction, qPAH) with stellar mass. Moreover, the sub-sample with robust qPAH measurements (N = 216) shows a similar behaviour between qPAH and gas-phase ∼ z ∼ 0, suggesting a universal relation: qPAH is constant (∼3.4%) above a metallicity of Z ∼ 0.5 Z⊙ and decreases to < 1% at metallicities ≲0.3 Z⊙. This indicates that metallicity is a good indicator of the interstellar medium properties that affect the balance between the formation and destruction of PAHs. The lack of a redshift evolution from z ∼ 0-2 also implies that above Z ∼ 0.5 Z⊙ the PAH emission effectively traces obscured luminosity and the previous locally calibrated PAH-SFR calibrations remain applicable in this metallicity regime. We observe a strong correlation between the obscured UV luminosity fraction (ratio of obscured to total luminosity) and stellar mass. Above the s tellar mass of M∗ > 5 × 109 M⊙, on average, more than half of the emitted luminosity is obscured, while there exists a non-negligible population of lower-mass galaxies with > 50% obscured fractions. At a fixed mass, the obscured fraction correlates with SFR surface density. This is a result of higher dust covering fractions in galaxies with more compact star-forming regions. Similarly, galaxies with high IRX (IR to UV luminosity) at a given mass or UV continuum slope (β) tend to have higher ΣSFR and shallower attenuation curves, owing to their higher effective dust optical depths and more compact star-forming regions.
• Sun, F., Helton, J. M., Egami, E., Hainline, K. N., Rieke, G. H., Willmer, C. N., Eisenstein, D. J., Johnson, B. D., Rieke, M. J., Robertson, B., Tacchella, S., Alberts, S., Baker, W. M., Bhatawdekar, R., Boyett, K., Bunker, A. J., Charlot, S., Chen, Z., Chevallard, J., , Curtis-Lake, E., et al. (2024). JADES: Resolving the Stellar Component and Filamentary Overdense Environment of Hubble Space Telescope (HST)-dark Submillimeter Galaxy HDF850.1 at z = 5.18. \apj, 961(1), 69.
• Topping, M. W., Stark, D. P., Endsley, R., Whitler, L., Hainline, K., Johnson, B. D., Robertson, B., Tacchella, S., Chen, Z., Alberts, S., Baker, W. M., Bunker, A. J., Carniani, S., Charlot, S., Chevallard, J., Curtis-Lake, E., DeCoursey, C., Egami, E., Eisenstein, D. J., , Ji, Z., et al. (2024). The UV continuum slopes of early star-forming galaxies in JADES. Monthly Notices of the Royal Astronomical Society, 529(4), 4087-4103. doi:10.1093/mnras/stae800
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  The power-law slope of the rest-ultraviolet (UV) continuum (fλ ∝ λβ) is a key metric of early star-forming galaxies, providing one of our only windows into the stellar populations and physical conditions of z ≳10 galaxies. Expanding upon previous studies with limited sample sizes, we leverage deep imaging from the JWST Advanced Deep Extragalactic Survey (JADES) to investigate the UV slopes of 179 z≳ 9 galaxies with apparent magnitudes of mF200W ⋍ 26–31, which display a median UV slope of β = −2.4. We compare to a statistical sample of z ⋍ 5–9 galaxies, finding a shift towards bluer rest-UV colours at all MUV. The most UV-luminous z ≳ 9 galaxies are significantly bluer than their lower redshift counterparts, representing a dearth of moderately red galaxies within the first 500 Myr. At yet earlier times, the z ≳ 11 galaxy population exhibits very blue UV slopes, implying very low impact from dust attenuation. We identify a robust sample of 44 galaxies with β ≲ −2.8, which have spectral energy distributions requiring models of density-bounded H II regions and median ionizing photon escape fractions of 0.51 to reproduce. Their rest-optical colours imply that this sample has weaker emission lines (median mF356W − mF444W = 0.19 mag) than typical galaxies (median mF356W − mF444W = 0.39 mag), consistent with the inferred escape fractions. This sample consists of relatively low stellar masses (median log(M/M⊙) = 7.5 ± 0.2), and specific star formation rates (sSFRs; median = 79 Gyr−1) nearly twice that of our full galaxy sample (median sSFRs = 44 Gyr−1), suggesting these objects are more common among systems experiencing a recent upturn in star formation. We demonstrate that the shutoff of star formation provides an alternative solution for modelling of extremely blue UV colours, making distinct predictions for the rest-optical emission of these galaxies. Future spectroscopy will be required to distinguish between these physical pictures.
• Topping, M. W., Stark, D. P., Endsley, R., Whitler, L., Hainline, K., Johnson, B. D., Robertson, B., Tacchella, S., Chen, Z., Alberts, S., Baker, W. M., Bunker, A. J., Carniani, S., Charlot, S., Chevallard, J., Curtis-Lake, E., DeCoursey, C., Egami, E., Eisenstein, D. J., , Ji, Z., et al. (2024). The UV continuum slopes of early star-forming galaxies in JADES. \mnras, 529(4), 4087-4103.
• Tripodi, R., D'Eugenio, F., Maiolino, R., Curti, M., Scholtz, J., Tacchella, S., Marconcini, C., Bunker, A. J., Trussler, J. A., Cameron, A. J., Arribas, S., Baker, W. M., Brada{\v{c}}, M., Carniani, S., Charlot, S., Ji, X., Ji, Z., Robertson, B., {\"Ubler}, H., , Venturi, G., et al. (2024). Spatially resolved emission lines in galaxies at 4 \ensuremath{\leq} z < 10 from the JADES survey: Evidence for enhanced central star formation. \aap, 692, A184.
• Trussler, J. A., Conselice, C. J., Adams, N., Austin, D., Ferreira, L., Harvey, T., Li, Q., Vijayan, A. P., Wilkins, S. M., Windhorst, R. A., Bhatawdekar, R., Cheng, C., Coe, D., Cohen, S. H., Driver, S. P., Frye, B., Grogin, N. A., Hathi, N., Jansen, R. A., , Koekemoer, A., et al. (2024). EPOCHS IX. When cosmic dawn breaks: evidence for evolved stellar populations in 7 < z < 12 galaxies from PEARLS GTO and public NIRCam imaging. \mnras, 527(4), 11627-11650.
• Trussler, J., Conselice, C., Adams, N., Austin, D., Ferreira, L., Harvey, T., Li, Q., Vijayan, A., Wilkins, S., Windhorst, R., Bhatawdekar, R., Cheng, C., Coe, D., Cohen, S., Driver, S., Frye, B., Grogin, N., Hathi, N., Jansen, R., , Koekemoer, A., et al. (2024). EPOCHS IX. When cosmic dawn breaks: Evidence for evolved stellar populations in 7 < z < 12 galaxies from PEARLS GTO and public NIRCam imaging. Monthly Notices of the Royal Astronomical Society, 527(4). doi:10.1093/mnras/stad3877
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  The presence of evolved stars in high-redshift galaxies can place valuable indirect constraints on the onset of star formation in the Universe. Thus, we use PEARLS GTO (Prime Extragalactic Areas for Reionization and Lensing Science Guaranteed Time Observations) and public NIRCam (Near Infrared Camera) photometric data to search for Balmer-break candidate galaxies at 7 < z < 12. We find that our Balmer-break candidates at z ∼10.5 tend to be older (115 Myr), have lower inferred [O iii] + Hβ equivalent widths (120 Å), have lower specific star formation rates (6 Gyr-1) and redder UV slopes (β =-1.8) than our control sample of galaxies. However, these trends all become less strong at z ∼8, where the F444W filter now probes the strong rest-frame optical emission lines, thus providing additional constraints on the current star formation activity of these galaxies. Indeed, the bursty nature of epoch of reionization galaxies can lead to a disconnect between their current spectral energy distribution (SED) profiles and their more extended star formation histories. We discuss how strong emission lines, the cumulative effect of weak emission lines, dusty continua, and active galactic nuclei can all contribute to the photometric excess seen in the rest-frame optical, thus mimicking the signature of a Balmer break. Additional medium-band imaging will thus be essential to more robustly identify Balmer-break galaxies. However, the Balmer break alone cannot serve as a definitive proxy for the stellar age of galaxies, being complexly dependent on the star formation history. Ultimately, deep Near Infrared Spectrograph (NIRSpec) continuum spectroscopy and Mid-Infrared Instrument (MIRI) imaging will provide the strongest indirect constraints on the formation era of the first galaxies in the Universe, thereby revealing when cosmic dawn breaks.
• Williams, C. C., Alberts, S., Ji, Z., Hainline, K. N., Lyu, J., Rieke, G., Endsley, R., Suess, K. A., Sun, F., Johnson, B. D., Florian, M., Shivaei, I., Rujopakarn, W., Baker, W. M., Bhatawdekar, R., Boyett, K., Bunker, A. J., Cameron, A. J., Carniani, S., , Charlot, S., et al. (2024). The Galaxies Missed by Hubble and ALMA: The Contribution of Extremely Red Galaxies to the Cosmic Census at 3 < z < 8. \apj, 968(1), 34.
• Williams, C., Alberts, S., Ji, Z., Hainline, K., Lyu, J., Rieke, G., Endsley, R., Suess, K., Sun, F., Johnson, B., Florian, M., Shivaei, I., Rujopakarn, W., Baker, W., Bhatawdekar, R., Boyett, K., Bunker, A., Cameron, A., Carniani, S., , Charlot, S., et al. (2024). The Galaxies Missed by Hubble and ALMA: The Contribution of Extremely Red Galaxies to the Cosmic Census at 3 < z < 8. Astrophysical Journal, 968(1). doi:10.3847/1538-4357/ad3f17
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  Using deep JWST imaging from JADES, JEMS, and SMILES, we characterize optically faint and extremely red galaxies at z > 3 that were previously missing from galaxy census estimates. The data indicate the existence of abundant, dusty, and poststarburst-like galaxies down to 108 M ⊙, below the sensitivity limit of Spitzer and the Atacama Large Millimeter/submillimeter Array (ALMA). Modeling the NIRCam and Hubble Space Telescope (HST) photometry of these red sources can result in extremely high values for both stellar mass and star formation rate (SFR); however, including seven MIRI filters out to 21 μm results in decreased masses (median 0.6 dex for log 10 ( M ∗ / M ⊙ ) > 10) and SFRs (median 10× for SFR > 100 M ⊙ yr−1). At z > 6, our sample includes a high fraction of “little red dots” (LRDs; NIRCam-selected dust-reddened active galactic nucleus (AGN) candidates). We significantly measure older stellar populations in the LRDs out to rest-frame 3 μm (the stellar bump) and rule out a dominant contribution from hot dust emission, a signature of AGN contamination to stellar population measurements. This allows us to measure their contribution to the cosmic census at z > 3, below the typical detection limits of ALMA (L IR < 1012 L ⊙). We find that these sources, which are overwhelmingly missed by HST and ALMA, could effectively double the obscured fraction of the star formation rate density at 4 < z < 6 compared to some estimates, showing that prior to JWST, the obscured contribution from fainter sources could be underestimated. Finally, we identify five sources with evidence for Balmer breaks and high stellar masses at 5.5 < z < 7.7. While spectroscopy is required to determine their nature, we discuss possible measurement systematics to explore with future data.
• Witstok, J., Smit, R., Saxena, A., Jones, G. C., Helton, J. M., Sun, F., Maiolino, R., Kumari, N., Stark, D. P., Bunker, A. J., Arribas, S., Baker, W. M., Bhatawdekar, R., Boyett, K., Cameron, A. J., Carniani, S., Charlot, S., Chevallard, J., Curti, M., , Curtis-Lake, E., et al. (2024). Inside the bubble: exploring the environments of reionisation-era Lyman-\ensuremath{\alpha} emitting galaxies with JADES and FRESCO. \aap, 682, A40.
• Witstok, J., Smit, R., Saxena, A., Jones, G., Helton, J., Sun, F., Maiolino, R., Kumari, N., Stark, D., Bunker, A., Arribas, S., Baker, W., Bhatawdekar, R., Boyett, K., Cameron, A., Carniani, S., Charlot, S., Chevallard, J., Curti, M., , Curtis-Lake, E., et al. (2024). Inside the bubble: exploring the environments of reionisation-era Lyman- α emitting galaxies with JADES and FRESCO. Astronomy and Astrophysics, 682(Issue). doi:10.1051/0004-6361/202347176
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  We present a study of the environments of 17 Lyman-α emitting galaxies (LAEs) in the reionisation-era (5.8 < z < 8) identified by JWST/NIRSpec as part of the JWST Advanced Deep Extragalactic Survey (JADES). Unless situated in sufficiently (re)ionised regions, Lyman-α emission from these galaxies would be strongly absorbed by neutral gas in the intergalactic medium (IGM). We conservatively estimate sizes of the ionised regions required to reconcile the relatively low Lyman-α velocity offsets (Γ vLyα < 300kms-1) with moderately high Lyman-α escape fractions (fesc,Lyα > 5%) observed in our sample of LAEs, suggesting the presence of ionised hydrogen along the line of sight towards at least eight out of 17 LAEs. We find minimum physical 'bubble'sizes of the order of Rion ∼ 0.1- 1pMpc are required in a patchy reionisation scenario where ionised bubbles containing the LAEs are embedded in a fully neutral IGM. Around half of the LAEs in our sample are found to coincide with large-scale galaxy overdensities seen in FRESCO at z ∼ 5.8- 5.9 and z ∼ 7.3, suggesting Lyman-α transmission is strongly enhanced in such overdense regions, and underlining the importance of LAEs as tracers of the first large-scale ionised bubbles. Considering only spectroscopically confirmed galaxies, we find our sample of UV-faint LAEs (MUV ≳ -20mag) and their direct neighbours are generally not able to produce the required ionised regions based on the Lyman-α transmission properties, suggesting lower-luminosity sources likely play an important role in carving out these bubbles. These observations demonstrate the combined power of JWST multi-object and slitless spectroscopy in acquiring a unique view of the early Universe during cosmic reionisation via the most distant LAEs.
• Woodrum, C., Rieke, M., Ji, Z., Baker, W. M., Bhatawdekar, R., Bunker, A. J., Charlot, S., Curtis-Lake, E., Eisenstein, D. J., Hainline, K., Hausen, R., Helton, J. M., Hviding, R. E., Johnson, B. D., Robertson, B., Sun, F., Tacchella, S., Whitler, L., Williams, C. C., & Willmer, C. N. (2024). Using JADES NIRCam photometry to investigate the dependence of stellar mass inferences on the IMF in the early universe. Proceedings of the National Academy of Science, 121(42), e2317375121.
• Woodrum, C., Rieke, M., Ji, Z., Baker, W., Bhatawdekar, R., Bunker, A., Charlot, S., Curtis-Lake, E., Eisenstein, D., Hainline, K., Hausen, R., Helton, J., Hviding, R., Johnson, B., Robertson, B., Sun, F., Tacchella, S., Whitler, L., Williams, C., & Willmer, C. (2024). Using JADES NIRCam photometry to investigate the dependence of stellar mass inferences on the IMF in the early universe. Proceedings of the National Academy of Sciences of the United States of America, 121(42). doi:10.1073/pnas.2317375121
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  The detection of numerous and relatively bright galaxies at redshifts z > 9 has prompted new investigations into the star-forming properties of high-redshift galaxies. Using local forms of the initial mass function (IMF) to estimate stellar masses of these galaxies from their light output leads to galaxy masses that are at the limit allowed for the state of the Lambda Cold Dark Matter (ΛCDM) Universe at their redshift. We explore how varying the IMF assumed in studies of galaxies in the early universe changes the inferred values for the stellar masses of these galaxies. We infer galaxy properties with the spectral energy distribution (SED) fitting code Prospector using varying IMF parameterizations for a sample of 102 galaxies with photometry from the James Webb Space Telescope, JWST Advanced Deep Extragalactic Survey that are spectroscopically confirmed to be at z > 6.7, with additional photometry from the JWST Extragalactic Medium Band Survey for twenty-one of the galaxies. We demonstrate that models with stellar masses reduced by a factor of three or more do not affect the modeled SED.
• Woodrum, C., Williams, C. C., Rieke, M., Hainline, K. N., Hviding, R. E., Ji, Z., Kennicutt, R., & Willmer, C. N. (2024). Active Galactic Nuclei in the Green Valley at z \ensuremath{\sim} 0.7. \apj, 974(2), 305.
• Zhao, X., Civano, F., Willmer, C. N., Bonoli, S., Chen, C., Creech, S., Dupke, R., Fornasini, F. M., Jansen, R. A., Kikuta, S., Koekemoer, A. M., Laha, S., Marchesi, S., O'Brien, R., Silver, R., Willner, S., Windhorst, R. A., Yan, H., Alcaniz, J., , Benitez, N., et al. (2024). PEARLS: NuSTAR and XMM-Newton Extragalactic Survey of the JWST North Ecliptic Pole Time-domain Field II. \apj, 965(2), 188.
• , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , ., , , ., et al. (2023). The James Webb Space Telescope Mission. Publications of the Astronomical Society of the Pacific, 135(1048). doi:10.1088/1538-3873/acd1b5
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  Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.
• Bagley, M. B., Finkelstein, S. L., Koekemoer, A. M., Ferguson, H. C., Haro, P. A., Dickinson, M., Kartaltepe, J. S., Papovich, C., Pérez-González, P. G., Pirzkal, N., Somerville, R. S., Willmer, C. N., Yang, G., Aaron Yung, L. Y., Fontana, A., Grazian, A., Grogin, N. A., Hirschmann, M., Kewley, L. J., , Kirkpatrick, A., et al. (2023). CEERS Epoch 1 NIRCam Imaging: Reduction Methods and Simulations Enabling Early JWST Science Results. Astrophysical Journal Letters, 946(Issue 1). doi:10.3847/2041-8213/acbb08
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  We present the data release and data reduction process for the Epoch 1 NIRCam observations for the Cosmic Evolution Early Release Science Survey (CEERS). These data consist of NIRCam imaging in six broadband filters (F115W, F150W, F200W, F277W, F356W and F444W) and one medium-band filter (F410M) over four pointings, obtained in parallel with primary CEERS MIRI observations. We reduced the NIRCam imaging with the JWST Calibration Pipeline, with custom modifications and reduction steps designed to address additional features and challenges with the data. Here we provide a detailed description of each step in our reduction and a discussion of future expected improvements. Our reduction process includes corrections for known prelaunch issues such as 1/f noise, as well as in-flight issues including snowballs, wisps, and astrometric alignment. Many of our custom reduction processes were first developed with prelaunch simulated NIRCam imaging over the full 10 CEERS NIRCam pointings. We present a description of the creation and reduction of this simulated data set in the Appendix. We provide mosaics of the real images in a public release, as well as our reduction scripts with detailed explanations to allow users to reproduce our final data products. These represent one of the first official public data sets released from the Directors Discretionary Early Release Science (DD-ERS) program.
• Bunker, A. J., Saxena, A., Cameron, A. J., Willott, C. J., Curtis-Lake, E., Jakobsen, P., Carniani, S., Smit, R., Maiolino, R., Witstok, J., Curti, M., D'eugenio, F., Jones, G. C., Ferruit, P., Arribas, S., Charlot, S., Chevallard, J., Giardino, G., De Graaff, A., , Looser, T. J., et al. (2023). JADES NIRSpec Spectroscopy of GN-z11: Lyman- α emission and possible enhanced nitrogen abundance in a z = 10.60 luminous galaxy. Astronomy and Astrophysics, 677. doi:10.1051/0004-6361/202346159
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  We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous candidate z>10 Lyman break galaxy in the GOODS-North field with MUV =-21.5. We derive a redshift of z = 10.603 (lower than previous determinations) based on multiple emission lines in our low and medium resolution spectra over 0.7- 5.3 μm. We significantly detect the continuum and measure a blue rest-UV spectral slope of β =-2.4. Remarkably, we see spatially extended Lyman-α in emission (despite the highly neutral intergalactic medium expected at this early epoch), offset 555 km s-1 redwards of the systemic redshift. From our measurements of collisionally excited lines of both low and high ionisation (including [O II] λ3727, [Ne III] λ3869, and C III] λ1909), we infer a high ionisation parameter (log U ∼-2). We detect the rarely seen N IV] λ1486 and N III] λ1748 lines in both our low and medium resolution spectra, with other high ionisation lines seen in the low resolution spectrum, such as He II (blended with O III]) and C IV (with a possible P-Cygni profile). Based on the observed rest-UV line ratios, we cannot conclusively rule out photoionisation from an active galactic nucleus (AGN), although the high C III]/He II and N III]/He II ratios are compatible with a star formation explanation. If the observed emission lines are powered by star formation, then the strong N III] λ1748 observed may imply an unusually high N/O abundance. Balmer emission lines (Hγ, Hδ) are also detected, and if powered by star formation rather than an AGN, we infer a star formation rate of ∼20-30 M⊙ yr-1 (depending on the initial mass function) and low dust attenuation. Our NIRSpec spectroscopy confirms that GN-z11 is a remarkable galaxy with extreme properties seen 430 Myr after the Big Bang.
• Cameron, A. J., Saxena, A., Bunker, A. J., D'eugenio, F., Carniani, S., Maiolino, R., Curtis-Lake, E., Ferruit, P., Jakobsen, P., Arribas, S., Bonaventura, N., Charlot, S., Chevallard, J., Curti, M., Looser, T. J., Maseda, M. V., Rawle, T., Rodríguez Del Pino, B., Smit, R., , Übler, H., et al. (2023). JADES: Probing interstellar medium conditions at z ∼ 5.5-9.5 with ultra-deep JWST/NIRSpec spectroscopy. Astronomy and Astrophysics, 677. doi:10.1051/0004-6361/202346107
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  We present emission-line ratios from a sample of 27 Lyman-break galaxies from z∼ 5.5-9.5 with-17.0< M1500 5.5 spectra. We find that the emission-line ratios exhibited by these z∼ 5.5-9.5 galaxies occupy clearly distinct regions of line-ratio space compared to typical z∼ 0-3 galaxies, instead being more consistent with extreme populations of lower-redshift galaxies. This is best illustrated by the [O III]/[O II] ratio, tracing interstellar medium (ISM) ionisation, in which we observe more than half of our sample to have [O III]/[O II] > 10. Our high signal-to-noise spectra reveal more than an order of magnitude of scatter in line ratios such as [O II]/Hβ and [O III]/[O II], indicating significant diversity in the ISM conditions within the sample. We find no convincing detections of [N II] λ6583 in our sample, either in individual galaxies, or a stack of all G395M/F290LP spectra. The emission-line ratios observed in our sample are generally consistent with galaxies with extremely high ionisation parameters (log U∼-1.5), and a range of metallicities spanning from ∼0.1 × Z⊙ to higher than ∼0.3 × Z⊙, suggesting we are probing low-metallicity systems undergoing periods of rapid star formation, driving strong radiation fields. These results highlight the value of deep observations in constraining the properties of individual galaxies, and hence probing diversity within galaxy population.
• Cheng, C., Huang, J. S., Smail, I., Yan, H., Cohen, S. H., Jansen, R. A., Windhorst, R. A., Ma, Z., Koekemoer, A., Willmer, C. N., Willner, S. P., Diego, J. M., Frye, B., Conselice, C. J., Ferreira, L., Petric, A., Yun, M., Gim, H. B., Polletta, M. d., , Duncan, K. J., et al. (2023). JWST’s PEARLS: A JWST/NIRCam View of ALMA Sources. Astrophysical Journal Letters, 942(Issue 1). doi:10.3847/2041-8213/aca9d0
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  We report the results of James Webb Space Telescope/NIRCam observations of 19 (sub)millimeter sources detected by the Atacama Large Millimeter Array (ALMA). The accurate ALMA positions allowed unambiguous identifications of their NIRCam counterparts. Taking gravitational lensing into account, these represent 16 distinct galaxies in three fields and constitute the largest sample of its kind to date. The counterparts’ spectral energy distributions cover from rest-frame ultraviolet to near-IR and provide photometric redshifts (1 < z < 4.5) and stellar masses (M * > 1010.5 M ⊙), which are similar to submillimeter galaxies (SMGs) studied previously. However, our sample is fainter in (sub)millimeter than the classic SMG samples are, and our sources exhibit a wider range of properties. They have dust-embedded star formation rates as low as 10 M ⊙ yr−1, and the sources populate both the star-forming main sequence and the quiescent categories. The deep NIRCam data allow us to study the rest-frame near-IR morphologies. Excluding two multiply imaged systems and one quasar, the majority of the remaining sources are disk-like and show either little or no disturbance. This suggests that secular growth is a potential route for the assembly of high-mass disk galaxies. While a few objects have large disks, the majority have small disks (median half-mass radius of 1.6 kpc). At this time, it is unclear whether this is due to the prevalence of small disks at these redshifts or some unknown selection effects of deep ALMA observations. A larger sample of ALMA sources with NIRCam observations will be able to address this question.
• Curtis-Lake, E., Carniani, S., Cameron, A., Charlot, S., Jakobsen, P., Maiolino, R., Bunker, A., Witstok, J., Smit, R., Chevallard, J., Willott, C., Ferruit, P., Arribas, S., Bonaventura, N., Curti, M., D’Eugenio, F., Franx, M., Giardino, G., Looser, T. J., , Lützgendorf, N., et al. (2023). Spectroscopic confirmation of four metal-poor galaxies at z = 10.3–13.2. Nature Astronomy, 7(Issue 5). doi:10.1038/s41550-023-01918-w
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  Finding and characterizing the first galaxies that illuminated the early universe at cosmic dawn is pivotal to understand the physical conditions and the processes that led to the formation of the first stars. In the first few months of operations, imaging from the James Webb Space Telescope (JWST) has been used to identify tens of candidates of galaxies at redshift (z) greater than 10, less than 450 million years after the Big Bang. However, none of such candidates has yet been confirmed spectroscopically, leaving open the possibility that they are actually low-redshift interlopers. Here we present spectroscopic confirmation and analysis of four galaxies unambiguously detected at redshift 10.3 ≤ z ≤ 13.2, previously selected from JWST Near Infrared Camera imaging. The spectra reveal that these primeval galaxies are metal poor, have masses on the order of about 107–108 solar masses and young ages. The damping wings that shape the continuum close to the Lyman edge provide constraints on the neutral hydrogen fraction of the intergalactic medium from normal star-forming galaxies. These findings demonstrate the rapid emergence of the first generations of galaxies at cosmic dawn.
• Diego, J., Meena, A., Adams, N., Broadhurst, T., Dai, L., Coe, D., Frye, B., Kelly, P., Koekemoer, A., Pascale, M., Willner, S., Zackrisson, E., Zitrin, A., Windhorst, R., Cohen, S., Jansen, R., Summers, J., Tompkins, S., Conselice, C., , Driver, S., et al. (2023). JWST's PEARLS: A new lens model for ACT-CL J010-4915, "El Gordo" and the first red supergiant star at cosmological distances discovered by JWST. Astronomy and Astrophysics, 672(Issue). doi:10.1051/0004-6361/202245238
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  The first James Webb Space Telescope (JWST) data on the massive colliding cluster El Gordo allow for 23 known families of multiply lensed images to be confirmed and for eight new members of these families to be identified. Based on these families, which have been confirmed spectroscopically by MUSE, we derived an initial lens model. This model guided the identification of 37 additional families of multiply lensed galaxies, among which 28 are entirely new systems, and nine were previously known. The initial lens model determined geometric redshifts for the 37 new systems. The geometric redshifts agree reasonably well with spectroscopic or photometric redshifts when those are available. The geometric redshifts enable two additional models that include all 60 families of multiply lensed galaxies spanning a redshift range 2 < z < 6. The derived dark-matter distribution confirms the double-peak configuration of mass found by earlier work with the southern and northern clumps having similar masses. We confirm that El Gordo is the most massive known cluster at z > 0.8 and has an estimated virial mass close the maximum mass allowed by standard cosmological models. The JWST images also reveal the presence of small-mass perturbers that produce small lensing distortions. The smallest of these is consistent with being a dwarf galaxy at z = 0.87 and has an estimated mass of 3.8× 109 Mamiddot;, making it the smallest substructure found at z > 0.5. The JWST images also show several candidate caustic-crossing events. One of them is detected at high significance at the expected position of the critical curve and is likely a red supergiant star at z = 2.1878. This would be the first red supergiant found at cosmological distances. The cluster lensing should magnify background objects at z > 6, making more of them visible than in blank fields of a similar size, but there appears to be a deficiency of such objects.
• Dressler, A., Vulcani, B., Treu, T., Rieke, M., Burns, C., Calabrò, A., Bonchi, A., Castellano, M., Fontana, A., Leethochawalit, N., Mason, C., Merlin, E., Morishita, T., Paris, D., Bradac, M., Mercurio, A., Nanayakkara, T., Poggianti, B. M., Santini, P., , Wang, X., et al. (2023). Early Results from GLASS-JWST. XVII. Building the First Galaxies—Chapter 1. Star Formation Histories for 5 < z < 7 Galaxies. Astrophysical Journal Letters, 947(Issue 2). doi:10.3847/2041-8213/ac9ebb
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  The JWST observations of high-redshift galaxies are used to measure their star formation histories—the buildup of stellar mass in the earliest galaxies. Here we use a novel analysis program, SEDz*, to compare near-IR spectral energy distributions for galaxies with redshifts 5 < z < 7 to combinations of stellar population templates evolved from z = 12. We exploit NIRCam imaging in seven wide bands covering 1-5 μm taken in the context of the GLASS-JWST-ERS program and use SEDz* to solve for well-constrained star formation histories for 24 exemplary galaxies. In this first look, we find a variety of histories, from long, continuous star formation over 5 < z < 12 to short but intense starbursts, sometimes repeating, and, most commonly, contiguous mass buildup lasting ∼0.5 Myr, possibly the seeds of today’s typical M* galaxies.
• Duncan, K. J., Windhorst, R. A., Koekemoer, A. M., Röttgering, H. J., Cohen, S. H., Jansen, R. A., Summers, J., Tompkins, S., Hutchison, T. A., Conselice, C. J., Driver, S. P., Yan, H., Adams, N. J., Cheng, C., Coe, D., Diego, J. M., Dole, H., Frye, B., Gim, H. B., , Grogin, N. A., et al. (2023). JWST’s PEARLS: TN J1338–1942 – I. Extreme jet-triggered star formation in a z = 4.11 luminous radio galaxy. Monthly Notices of the Royal Astronomical Society, 522(3), 4548-4564. doi:10.1093/mnras/stad1267
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  We present the first JWST observations of the $z=4.11$ luminous radio galaxy TN J1338-1942, obtained as part of the ``Prime Extragalactic Areas for Reionization and Lensing Science'' (``PEARLS'') project. Our NIRCam observations, designed to probe the key rest-frame optical continuum and emission line features at this redshift, enable resolved spectral energy distribution modelling that incorporates both a range of stellar population assumptions and radiative shock models. With an estimated stellar mass of $\log_{10}(M/\text{M}_{\odot}) \sim 10.9$, TN J1338--1942 is confirmed to be one of the most massive galaxies known at this epoch. Our observations also reveal extremely high equivalent-width nebular emission coincident with the luminous AGN jets that is best fit by radiative shocks surrounded by extensive recent star-formation. We estimate the total star-formation rate (SFR) could be as high as $\sim1600\,\text{M}_{\odot}\,\text{yr}^{-1}$, with the SFR that we attribute to the jet induced burst conservatively $\gtrsim500\,\text{M}_{\odot}\,\text{yr}^{-1}$. The mass-weighted age of the star-formation, $t_{\text{mass}}
• Hernán-Caballero, A., Willmer, C. N., Varela, J., López-Sanjuan, C., Marín-Franch, A., Vázquez Ramió, H., Civera, T., Ederoclite, A., Muniesa, D., Cenarro, J., Bonoli, S., Dupke, R., Lim, J., Chaves-Montero, J., Laur, J., Hernández-Monteagudo, C., Fernández-Ontiveros, J. A., Fernández-Soto, A., Díaz-García, L. A., , González Delgado, R. M., et al. (2023). J-NEP: 60-band photometry and photometric redshifts for the James Webb Space Telescope North Ecliptic Pole Time-Domain Field. Astronomy and Astrophysics, 671(Issue). doi:10.1051/0004-6361/202244759
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  The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) will observe approximately one-third of the northern sky with a set of 56 narrow-band filters using the dedicated 2.55 m Javalambre Survey Telescope (JST) at the Javalambre Astrophysical Observatory. Prior to the installation of the main camera, in order to demonstrate the scientific potential of J-PAS, two small surveys were performed with the single-CCD Pathfinder camera: miniJPAS (∼1 deg2 along the Extended Groth Strip), and J-NEP (∼0.3 deg2 around the JWST North Ecliptic Pole Time Domain Field), including all 56 J-PAS filters as well as u, g, r, and i. J-NEP is ∼0.5-1.0 mag deeper than miniJPAS, providing photometry for 24,618 r-band-detected sources and photometric redshifts (photo-z) for the 6662 sources with r < 23. In this paper, we describe the photometry and photo-z of J-NEP and demonstrate a new method for the removal of systematic offsets in the photometry based on the median colours of galaxies, which we call 'galaxy locus recalibration'. This method does not require spectroscopic observations except in a few reference pointings and, unlike previous methods, is directly applicable to the whole J-PAS survey. We use a spectroscopic sample of 787 galaxies to test the photo-z performance for J-NEP and in comparison to miniJPAS. We find that the deeper J-NEP observations result in a factor ∼1.5- 2 decrease in σNMAD (a robust estimate of the standard deviation of the photo-z error) and η (the outlier rate) relative to miniJPAS for r > 21.5 sources, but no improvement in brighter ones, which is probably because of systematic uncertainties. We find the same relation between σNMAD and odds in J-NEP and miniJPAS, which suggests that we will be able to predict the σNMAD of any set of J-PAS sources from their odds distribution alone, with no need for additional spectroscopy to calibrate the relation. We explore the causes of photo-z outliers and find that colour-space degeneracy at low S/N, photometry artefacts, source blending, and exotic spectra are the most important factors.
• Hyun, M., Im, M., Smail, I. R., Cotton, W. D., Birkin, J. E., Kikuta, S., Shim, H., Willmer, C. N., Condon, J. J., Windhorst, R. A., Cohen, S. H., Jansen, R. A., Ly, C., Matsuda, Y., Fazio, G. G., Swinbank, A. M., & Yan, H. (2023). The JCMT SCUBA-2 Survey of the James Webb Space Telescope North Ecliptic Pole Time-Domain Field. Astrophysical Journal, Supplement Series, 264(Issue 1). doi:10.3847/1538-4365/ac9bf4
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  The James Webb Space Telescope Time-Domain Field (JWST-TDF) is an ∼14′ diameter field near the North Ecliptic Pole that will be targeted by one of the JWST Guaranteed Time Observations programs. Here, we describe our James Clerk Maxwell Telescope SCUBA-2 850 μm imaging of the JWST-TDF and present the submillimeter source catalog and properties. We also present a catalog of radio sources from Karl J. Jansky Very Large Array 3 GHz observations of the field. These observations were obtained to aid JWST's study of dust-obscured galaxies that contribute significantly to cosmic star formation at high redshifts. Our deep 850 μm map covers the JWST-TDF at a noise level of σ 850µm = 1.0 mJy beam−1, detecting 83/31 sources in the main/supplementary signal-to-noise ratio (S/N > 4 / S/N = 3.5-4) sample, respectively. The 3 GHz observations cover a 24′ diameter field with a 1σ noise of 1 μJy beam−1 at a 0.″7 FWHM. We identified eighty-five 3 GHz counterparts to sixty-six 850 μm sources and then matched these with multiwavelength data from the optical to the mid-infrared wave bands. We performed spectral energy distribution fitting for 61 submillimeter galaxies (SMGs) matched with optical/near-infrared data, and found that SMGs at S/N > 4 have a median value of z phot = 2.22 ± 0.12, star formation rates of 300 ± 40 M ⊙ yr−1 (Chabrier initial mass function), and typical cold dust masses of 5.9 ± 0.7 × 108 M ⊙, in line with bright SMGs from other surveys. The large cold dust masses indicate correspondingly large cool gas masses, which we suggest are a key factor necessary to drive the high star formation rates seen in this population.
• Juodžbalis, I., Conselice, C. J., Singh, M., Adams, N., Ormerod, K., Harvey, T., Austin, D., Volonteri, M., Cohen, S. H., Jansen, R. A., Summers, J., Windhorst, R. A., D'Silva, J. C., Koekemoer, A. M., Coe, D., Driver, S. P., Frye, B., Grogin, N. A., Marshall, M. A., , Nonino, M., et al. (2023). EPOCHS VII: discovery of high-redshift (6.5 < z < 12) AGN candidates in JWST ERO and PEARLS data. Monthly Notices of the Royal Astronomical Society, 525(Issue 1). doi:10.1093/mnras/stad2396
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  We present an analysis of a sample of robust high-redshift galaxies selected from the 'blank' fields of the Prime Extragalactic Areas for Reionization Science (PEARLS) survey and Early Release Observations (ERO) data from JWST with the aim of selecting candidate high-redshift active galactic nuclei (AGN). Sources were identified from this parent sample using a threefold selection procedure, which includes spectral energy distribution (SED) fitting to identify sources that are best fitted by AGN SED templates, a further selection based on the relative performance of AGN and non-AGN models, and finally morphological fitting to identify compact sources of emission, resulting in a purity-oriented procedure. Using this procedure, we identify a sample of nine AGN candidates at 6.5 < z < 12, from which we constrain their physical properties as well as measure a lower bound on the AGN fraction in this redshift range of 5 ± 1 per cent. As this is an extreme lower limit due to our focus on purity and our SEDs being calibrated for unobscured Type 1 AGN, this demonstrates that AGN are perhaps quite common at this early epoch. The rest-frame UV colours of our candidate objects suggest that these systems are potentially candidate obese black hole galaxies (OBGs). We also investigate Chandra and VLA maps of these areas from which we calculate detection limits. Of note is a z = 11.9 candidate source exhibiting an abrupt morphological shift in the reddest band as compared to bluer bands, indicating a potential merger or an unusually strong outflow.
• Kamieneski, P. S., Frye, B. L., Pascale, M., Cohen, S. H., Windhorst, R. A., Jansen, R. A., Yun, M. S., Cheng, C., Summers, J. S., Carleton, T., Harrington, K. C., Diego, J. M., Yan, H., Koekemoer, A. M., Willmer, C. N., Petric, A., Furtak, L. J., Foo, N., Conselice, C. J., , Coe, D., et al. (2023). Are JWST/NIRCam Color Gradients in the Lensed z = 2.3 Dusty Star-forming Galaxy El Anzuelo Due to Central Dust Attenuation or Inside-out Galaxy Growth?. Astrophysical Journal, 955(Issue 2). doi:10.3847/1538-4357/aceb4a
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  Gradients in the mass-to-light ratio of distant galaxies impede our ability to characterize their size and compactness. The long-wavelength filters of JWST’s NIRCam offer a significant step forward. For galaxies at Cosmic Noon (z ∼ 2), this regime corresponds to the rest-frame near-infrared, which is less biased toward young stars and captures emission from the bulk of a galaxy’s stellar population. We present an initial analysis of an extraordinary lensed dusty star-forming galaxy at z = 2.3 behind the El Gordo cluster (z = 0.87), named El Anzuelo (“The Fishhook”) after its partial Einstein-ring morphology. The far-UV to near-IR spectral energy distribution suggests an intrinsic star formation rate of 81 − 2 + 7 M ⊙ yr − 1 and dust attenuation A V ≈ 1.6, in line with other DSFGs on the star-forming main sequence. We develop a parametric lens model to reconstruct the source-plane structure of dust imaged by the Atacama Large Millimeter/submillimeter Array, far-UV to optical light from Hubble, and near-IR imaging with 8 filters of JWST/NIRCam, as part of the Prime Extragalactic Areas for Reionization and Lensing Science program. The source-plane half-light radius is remarkably consistent from ∼1 to 4.5 μm, despite a clear color gradient where the inferred galaxy center is redder than the outskirts. We interpret this to be the result of both a radially decreasing gradient in attenuation and substantial spatial offsets between UV- and IR-emitting components. A spatial decomposition of the SED reveals modestly suppressed star formation in the inner kiloparsec, which suggests that we are witnessing the early stages of inside-out quenching.
• Keel, W. C., Windhorst, R. A., Jansen, R. A., Cohen, S. H., Summers, J., Holwerda, B., Bradford, S. T., Robertson, C. D., Ferrami, G., Wyithe, S., Yan, H., Conselice, C. J., Driver, S. P., Robotham, A., Grogin, N. A., Willmer, C. N., Koekemoer, A. M., Frye, B. L., Hathi, N. P., , Ryan, R. E., et al. (2023). JWST’s PEARLS: Dust Attenuation and Gravitational Lensing in the Backlit-galaxy System VV 191. Astronomical Journal, 165(Issue 4). doi:10.3847/1538-3881/acbdff
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  We derive the spatial and wavelength behavior of dust attenuation in the multiple-armed spiral galaxy VV 191b using backlighting by the superimposed elliptical system VV 191a in a pair with an exceptionally favorable geometry for this measurement. Imaging using the James Webb Space Telescope and Hubble Space Telescope spans the wavelength range 0.3-4.5 μm with high angular resolution, tracing the dust in detail from 0.6-1.5 μm. Distinct dust lanes continue well beyond the bright spiral arms, and trace a complex web, with a very sharp radial cutoff near 1.7 Petrosian radii. We present attenuation profiles and coverage statistics in each band at radii 14-21 kpc. We derive the attenuation law with wavelength; the data both within and between the dust lanes clearly favor a stronger reddening behavior (R = A V /E B−V ≈ 2.0 between 0.6 and 0.9 μm, approaching unity by 1.5 μm) than found for starbursts and star-forming regions of galaxies. Power-law extinction behavior ∝λ −β gives β = 2.1 from 0.6-0.9 μm. R decreases at increasing wavelengths (R ≈ 1.1 between 0.9 and 1.5 μm), while β steepens to 2.5. Mixing regions of different column density flattens the wavelength behavior, so these results suggest a different grain population than in our vicinity. The NIRCam images reveal a lens arc and counterimage from a background galaxy at z ≈ 1, spanning 90° azimuthally at 2.″8 from the foreground elliptical-galaxy nucleus, and an additional weakly lensed galaxy. The lens model and imaging data give a mass/light ratio M/L B = 7.6 in solar units within the Einstein radius 2.0 kpc.
• Polletta, M., Nonino, M., Frye, B., Gargiulo, A., Bisogni, S., Garuda, N., Thompson, D., Lehnert, M., Pascale, M., Willner, S., Kamieneski, P., Leimbach, R., Cheng, C., Coe, D., Cohen, S., Conselice, C., Dai, L., Diego, J., Dole, H., , Driver, S., et al. (2023). Spectroscopy of the supernova H0pe host galaxy at redshift 1.78. Astronomy and Astrophysics, 675(Issue). doi:10.1051/0004-6361/202346964
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  Supernova (SN) H0pe was discovered as a new transient in James Webb Space Telescope (JWST) NIRCam images of the galaxy cluster PLCK G165.7+67.0 taken as part of the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) JWST GTO program (ID 1176) on 2023 March 30. The transient is a compact source associated with a background galaxy that is stretched and triply imaged by the strong gravitational lensing of the cluster. This paper reports spectra in the 950- 1370 nm observer frame of two of the galaxy images obtained with Large Binocular Telescope (LBT) Utility Camera in the Infrared (LUCI) in long-slit mode two weeks after the JWST observations. The individual and average spectra show the [O′ ¯II] λλ3727,3730 doublet and the Balmer and 4000 Åbreaks at redshift z = 1.783 ± 0.002. The code investigating galaxy emission (CIGALE) best-fit model of the spectral energy distribution indicates that the host galaxy of SN H0pe is massive (Mstar ≃ 6 × 1010 M⊙ after correcting for a magnification factor μ ~ 7) with a predominantly intermediate-age (~2 Gyr) stellar population, moderate extinction, and a magnification-corrected star formation rate ≃13 M⊙ yr-1, consistent with being below the main sequence of star formation. These properties suggest that H0pe might be a type Ia SN. Additional observations of SN H0pe and its host recently carried out with JWST (JWST-DD-4446; PI: B. Frye) will be able to both determine the SN classification and confirm its association with the galaxy analyzed in this work.
• Rieke, M. J., Kelly, D. M., Misselt, K., Stansberry, J., Boyer, M., Beatty, T., Egami, E., Florian, M., Greene, T. P., Hainline, K., Leisenring, J., Roellig, T., Schlawin, E., Sun, F., Tinnin, L., Williams, C. C., Willmer, C. N., Wilson, D., Clark, C. R., , Rohrbach, S., et al. (2023). Performance of NIRCam on JWST in Flight. Publications of the Astronomical Society of the Pacific, 135(Issue 1044). doi:10.1088/1538-3873/acac53
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  The Near Infrared Camera for the James Webb Space Telescope (JWST) is delivering the imagery that astronomers have hoped for ever since JWST was proposed back in the 1990s. In the Commissioning Period that extended from right after launch to early 2022 July, NIRCam has been subjected to a number of performance tests and operational checks. The camera is exceeding prelaunch expectations in virtually all areas, with very few surprises discovered in flight. NIRCam also delivered the imagery needed by the Wavefront Sensing Team for use in aligning the telescope mirror segments.
• Rieke, M. J., Robertson, B., Tacchella, S., Hainline, K., Johnson, B. D., Hausen, R., Ji, Z., Willmer, C. N., Eisenstein, D. J., Puskás, D., Alberts, S., Arribas, S., Baker, W. M., Baum, S., Bhatawdekar, R., Bonaventura, N., Boyett, K., Bunker, A. J., Cameron, A. J., , Carniani, S., et al. (2023). JADES Initial Data Release for the Hubble Ultra Deep Field: Revealing the Faint Infrared Sky with Deep JWST NIRCam Imaging. Astrophysical Journal, Supplement Series, 269(Issue 1). doi:10.3847/1538-4365/acf44d
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  JWST has revolutionized the field of extragalactic astronomy with its sensitive and high-resolution infrared view of the distant Universe. Adding to the new legacy of JWST observations, we present the first NIRCam imaging data release from the JWST Advanced Deep Extragalactic Survey (JADES), providing nine filters of infrared imaging of ∼25 arcmin2 covering the Hubble Ultra Deep Field and portions of Great Observatories Origins Deep Survey South. Utilizing 87 on-sky dual-filter hours of exposure time, these images reveal the deepest ever near-infrared view of this iconic field. We supply carefully constructed nine-band mosaics of the JADES bands, as well as matching reductions of five additional bands from the JWST Extragalactic Medium-band Survey. Combining with existing Hubble Space Telescope imaging, we provide 23-band space-based photometric catalogs and photometric redshifts for ≈47,500 sources. To promote broad engagement with JADES, we have created an interactive FitsMap website to provide an interface for professional researchers and the public to experience these JWST data sets. Combined with the first JADES NIRSpec data release, these public JADES imaging and spectroscopic data sets provide a new foundation for discoveries of the infrared Universe by the worldwide scientific community.
• Robertson, B. E., Tacchella, S., Johnson, B. D., Hainline, K., Whitler, L., Eisenstein, D. J., Endsley, R., Rieke, M., Stark, D. P., Alberts, S., Dressler, A., Egami, E., Hausen, R., Rieke, G., Shivaei, I., Williams, C. C., Willmer, C. N., Arribas, S., Bonaventura, N., , Bunker, A., et al. (2023). Identification and properties of intense star-forming galaxies at redshifts z > 10. Nature Astronomy, 7(Issue 5). doi:10.1038/s41550-023-01921-1
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  Surveys with the James Webb Space Telescope (JWST) have discovered candidate galaxies in the first 400 Myr of cosmic time. Preliminary indications have suggested these candidate galaxies may be more massive and abundant than previously thought. However, without confirmed distances, their inferred properties remain uncertain. Here we identify four galaxies located in the JWST Advanced Deep Extragalactic Survey Near-Infrared Camera imaging with photometric redshifts z of roughly 10–13. These galaxies include the first redshift z > 12 systems discovered with distances spectroscopically confirmed by JWST in a companion paper. Using stellar population modelling, we find the galaxies typically contain 100 million solar masses in stars, in stellar populations that are less than 100 million years old. The moderate star-formation rates and compact sizes suggest elevated star-formation rate surface densities, a key indicator of their formation pathways. Taken together, these measurements show that the first galaxies contributing to cosmic reionization formed rapidly and with intense internal radiation fields.
• Robertson, B. E., Tacchella, S., Johnson, B. D., Hausen, R., Alabi, A. B., Boyett, K., Bunker, A. J., Carniani, S., Egami, E., Eisenstein, D. J., Hainline, K. N., Helton, J. M., Ji, Z., Kumari, N., Lyu, J., Maiolino, R., Nelson, E. J., Rieke, M. J., Shivaei, I., , Sun, F., et al. (2023). Morpheus Reveals Distant Disk Galaxy Morphologies with JWST: The First AI/ML Analysis of JWST Images. Astrophysical Journal Letters, 942(Issue 2). doi:10.3847/2041-8213/aca086
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  The dramatic first images with JWST demonstrated its power to provide unprecedented spatial detail for galaxies in the high-redshift universe. Here, we leverage the resolution and depth of the JWST Cosmic Evolution Early Release Science Survey data in the Extended Groth Strip to perform pixel-level morphological classifications of galaxies in JWST F150W imaging using the Morpheus deep-learning framework for astronomical image analysis. By cross-referencing with existing photometric redshift catalogs from the Hubble Space Telescope (HST) CANDELS survey, we show that JWST images indicate the emergence of disk morphologies before z ∼ 2 and with candidates appearing as early as z ∼ 5. By modeling the light profile of each object and accounting for the JWST point-spread function, we find the high-redshift disk candidates have exponential surface brightness profiles with an average Sérsic index 〈n〉 = 1.04 and >90% displaying “disky” profiles (n < 2). Comparing with prior Morpheus classifications in CANDELS we find that a plurality of JWST disk galaxy candidates were previously classified as compact based on the shallower HST imagery, indicating that the improved optical quality and depth of the JWST helps to reveal disk morphologies that were hiding in the noise. We discuss the implications of these early disk candidates on theories for cosmological disk galaxy formation.
• Robotham, A., Windhorst, R., Jansen, R., Summers, J., Driver, S., Wilmer, C., Bellstedt, S., & D’Silva, J. (2023). Dynamic Wisp Removal in JWST NIRCam Images. Publications of the Astronomical Society of the Pacific, 135(1050). doi:10.1088/1538-3873/acea42
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  The James Webb Space Telescope (JWST) near-infrared camera has been found to exhibit serious wisp-like structures in four of its eight short-wavelength detectors. The exact structure and strength of these wisps is highly variable with the position and orientation of JWST, so the use of static templates is non-optimal. Here we investigate a dynamic strategy to mitigate these wisps using long-wavelength reference images. Based on a suite of experiments where we embed a worst-case scenario median-stacked wisp into wisp-free images, we define suitable parameters for our wisp removal strategy. Using this setup we re-process wisp-affected public Prime Extragalactic Areas for Reionization and Lensing Science data in the North Ecliptic Pole Time Domain Field, resulting in significant visual improvement in our detector frames and reduced noise in the final stacked images.
• Saxena, A., Robertson, B. E., Bunker, A. J., Endsley, R., Cameron, A. J., Charlot, S., Simmonds, C., Tacchella, S., Witstok, J., Willott, C., Carniani, S., Curtis-Lake, E., Ferruit, P., Jakobsen, P., Arribas, S., Chevallard, J., Curti, M., D'Eugenio, F., De Graaff, A., , Jones, G. C., et al. (2023). JADES: Discovery of extremely high equivalent width Lyman- α emission from a faint galaxy within an ionized bubble at z = 7.3. Astronomy and Astrophysics, 678. doi:10.1051/0004-6361/202346245
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  We report the discovery of a remarkable Lyα emitting galaxy at z = 7.2782, JADES-GS+53.16746-27.7720 (shortened to JADES-GS-z7-LA), with rest-frame equivalent width, EW0(Lyα) = 388.0 ± 88.8 Å and UV magnitude -17.0. The spectroscopic redshift is confirmed via rest-frame optical lines [O- ¯II], Hβ and [O- ¯III] in its JWST/NIRSpec Micro-Shutter Assembly (MSA) spectrum. The Lyα line is detected in both lower resolution (R ∼ 100) PRISM as well as medium resolution (R ∼ 1000) G140M grating spectra. The line spread function-deconvolved Lyα full width at half maximum in the grating is 383.9 ± 56.2 km s-1 and the Lyα velocity offset compared to the systemic redshift is 113.3 ± 80.0 km s-1, indicative of very little neutral gas or dust within the galaxy. We estimate the Lyα escape fraction to be > 70%. JADES-GS-z7-LA has a [O- ¯III]/[O- ¯II] ratio (O32) of 11.1 ± 2.2 and a ([O- ¯III] + [O- ¯II])/Hβ ratio (R23) of 11.2 ± 2.6, consistent with low metallicity and high ionization parameters. Deep NIRCam imaging also revealed a close companion source (separated by 0.23- ³), which exhibits similar photometry to that of JADES-GS-z7-LA, with a photometric excess in the F410M NIRCam image consistent with [O- ¯III] + Hβ emission at the same redshift. The spectral energy distribution of JADES-GS-z7-LA indicates a bursty star formation history, with a low stellar mass of 107† M·. Assuming that the Lyα transmission through the intergalactic medium is the same as its measured escape fraction, an ionized region of size > 1.5 pMpc is needed to explain the high Lyα EW and low velocity offset compared to systemic seen in JADES-GS-z7-LA. Owing to its UV-faintness, we show that it is incapable of single-handedly ionizing a region large enough to explain its Lyα emission. Therefore, we suggest that JADES-GS-z7-LA (and possibly the companion source) may be a part of a larger overdensity, presenting direct evidence of overlapping ionized bubbles at z > 7.
• Summers, J., Windhorst, R. A., Cohen, S. H., Jansen, R. A., Carleton, T., Kamieneski, P. S., Holwerda, B. W., Conselice, C. J., Adams, N. J., Frye, B. L., Diego, J. M., Willmer, C. N., Ortiz, R., Cheng, C., Pigarelli, A., Robotham, A., D’Silva, J. C., Tompkins, S., Driver, S. P., , Yan, H., et al. (2023). Magellanic System Stars Identified in SMACS J0723.3-7327 James Webb Space Telescope Early Release Observations Images. Astrophysical Journal, 958(Issue 2). doi:10.3847/1538-4357/acffb9
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  We identify 71 distant stars in James Webb Space Telescope/NIRCam early release observations (ERO) images of the field of galaxy cluster SMACS J0723.3-7327 (SMACS 0723). Given the relatively small (∼10°) angular separation between SMACS 0723 and the Large Magellanic Cloud (LMC), it is likely that these stars are associated with the LMC outskirts or the Leading Arm. This is further bolstered by a spectral energy distribution (SED) analysis, which suggests an excess of stars at a physical distance of 40-100 kpc, consistent with being associated with or located behind the Magellanic system. In particular, we find that the overall surface density of stars brighter than 27.0 mag in the field of SMACS 0723 is ∼2.3 times that of stars in a blank field with similar Galactic latitude (the North Ecliptic Pole Time Domain Field), and that the density of stars in the SMACS 0723 field with SED-derived distances consistent with the Magellanic system is ∼6.1 times larger than that of the blank field. The candidate stars at these distances are consistent with a stellar population at the same distance modulus with [Fe/H] = −1.0 and an age of ∼5.0 Gyr. On the assumption that all of the 71 stars are associated with the LMC, then the stellar density of the LMC at the location of the SMACS 0723 field is ∼740 stars kpc−3, which helps trace the density of stars in the LMC outskirts.
• Sun, F., Egami, E., Pirzkal, N., Rieke, M., Baum, S., Boyer, M., Boyett, K., Bunker, A. J., Cameron, A. J., Curti, M., Eisenstein, D. J., Gennaro, M., Greene, T. P., Jaffe, D., Kelly, D., Koekemoer, A. M., Kumari, N., Maiolino, R., Maseda, M., , Perna, M., et al. (2023). First Sample of Hα+[O iii]λ5007 Line Emitters at z > 6 Through JWST/NIRCam Slitless Spectroscopy: Physical Properties and Line-luminosity Functions. Astrophysical Journal, 953(Issue 1). doi:10.3847/1538-4357/acd53c
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  We present a sample of four emission-line galaxies at z = 6.11-6.35 that were serendipitously discovered using the commissioning data for the James Webb Space Telescope (JWST)/NIRCam wide-field slitless spectroscopy mode. One of them (at z = 6.11) has been reported previously, while the others are new discoveries. These sources are selected by the secure detections of both [O iii] λ5007 and Hα lines with other fainter lines, which were tentatively detected in some cases (e.g., [O ii] λ3727, [O iii] λ4959). In the [O iii]/Hβ-[N ii]/Hα Baldwin-Phillips-Terlevich diagram, these galaxies occupy the same parameter space as that of z ∼ 2 star-forming galaxies, indicating that they have been enriched rapidly to subsolar metallicities (∼0.4 Z ⊙), similar to galaxies with comparable stellar masses at much lower redshifts. The detection of strong Hα lines suggests a higher ionizing photon production efficiency within galaxies in the early universe. We find brightening of the [O iii] λ5007 line-luminosity function (LF) from z = 3 to 6, and weak or no redshift evolution of the Hα line LF from z = 2 to 6. Both LFs are underpredicted at z ∼ 6 by a factor of ∼10 in certain cosmological simulations. This further indicates a global Lyα photon escape fraction of 7%-10% at z ∼ 6, which is slightly lower than previous estimates through the comparison of the UV-derived star formation rate density and Lyα luminosity density. Our sample recovers 66 − 44 + 128 % of z = 6.0-6.6 galaxies in the survey volume with stellar masses greater than 5 × 108 M ⊙, suggesting the ubiquity of strong Hα and [O iii] line emitters in the Epoch of Reionization, which will be further uncovered in the era of JWST.
• Tacchella, S., Eisenstein, D. J., Hainline, K., Johnson, B. D., Baker, W. M., Helton, J. M., Robertson, B., Suess, K. A., Chen, Z., Nelson, E., Puskás, D., Sun, F., Alberts, S., Egami, E., Hausen, R., Rieke, G., Rieke, M., Shivaei, I., Williams, C. C., , Willmer, C. N., et al. (2023). JADES Imaging of GN-z11: Revealing the Morphology and Environment of a Luminous Galaxy 430 Myr after the Big Bang. Astrophysical Journal, 952(Issue 1). doi:10.3847/1538-4357/acdbc6
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  We present JWST NIRCam nine-band near-infrared imaging of the luminous z = 10.6 galaxy GN-z11 from the JWST Advanced Deep Extragalactic Survey of the GOODS-N field. We find a spectral energy distribution (SED) entirely consistent with the expected form of a high-redshift galaxy: a clear blue continuum from 1.5 to 4 μm with a complete dropout in F115W. The core of GN-z11 is extremely compact in JWST imaging. We analyze the image with a two-component model, using a point source and a Sérsic profile that fits to a half-light radius of 200 pc and an index n = 0.9. We find a low-surface-brightness haze about 0.″4 to the northeast of the galaxy, which is most likely a foreground object but might be a more extended component of GN-z11. At a spectroscopic redshift of 10.60 (Bunker et al. 2023), the comparison of the NIRCam F410M and F444W images spans the Balmer jump. From population-synthesis modeling, here assuming no light from an active galactic nucleus, we reproduce the SED of GN-z11, finding a stellar mass of ∼109 M ⊙, a star formation rate of ∼20 M ⊙ yr−1, and a young stellar age of ∼20 Myr. Since massive galaxies at high redshift are likely to be highly clustered, we search for faint neighbors of GN-z11, finding nine galaxies out to ∼5 comoving Mpc transverse with photometric redshifts consistent with z = 10.6, and a tenth more tentative dropout only 3″ away. This is consistent with GN-z11 being hosted by a massive dark-matter halo (≈8 × 1010 M ⊙), though lower halo masses cannot be ruled out.
• Tacchella, S., Johnson, B. D., Robertson, B. E., Carniani, S., D'Eugenio, F., Kumari, N., Maiolino, R., Nelson, E. J., Suess, K. A., Übler, H., Williams, C. C., Adebusola, A., Alberts, S., Arribas, S., Bhatawdekar, R., Bonaventura, N., Bowler, R. A., Bunker, A. J., Cameron, A. J., , Curti, M., et al. (2023). JWST NIRCam + NIRSpec: Interstellar medium and stellar populations of young galaxies with rising star formation and evolving gas reservoirs. Monthly Notices of the Royal Astronomical Society, 522(Issue 4). doi:10.1093/mnras/stad1408
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  We present an interstellar medium and stellar population analysis of three spectroscopically confirmed z > 7 galaxies in the Early Release Observations JWST/NIRCam and JWST/NIRSpec data of the SMACS J0723.3-7327 cluster. We use the Bayesian spectral energy distribution-fitting code PROSPECTOR with a flexible star formation history (SFH), a variable dust attenuation law, and a self-consistent model of nebular emission (continuum and emission lines). Importantly, we self-consistently fit both the emission line fluxes from JWST/NIRSpec and the broad-band photometry from JWST/NIRCam, taking into account slit-loss effects. We find that these three z=7.6-8.5 galaxies (M∗~108M⊙) are young with rising SFHs and mass-weighted ages of 3-4 Myr, though we find indications for underlying older stellar populations. The inferred gas-phase metallicities broadly agree with the direct metallicity estimates from the auroral lines. The galaxy with the lowest gas-phase metallicity (Zgas= 0.06 Z⊙) has a steeply rising SFH, is very compact (
• Williams, C. C., Tacchella, S., Maseda, M. V., Robertson, B. E., Johnson, B. D., Willott, C. J., Eisenstein, D. J., Willmer, C. N., Ji, Z., Hainline, K. N., Helton, J. M., Alberts, S., Baum, S., Bhatawdekar, R., Boyett, K., Bunker, A. J., Carniani, S., Charlot, S., Chevallard, J., , Curtis-Lake, E., et al. (2023). JEMS: A Deep Medium-band Imaging Survey in the Hubble Ultra Deep Field with JWST NIRCam and NIRISS. Astrophysical Journal, Supplement Series, 268(Issue 2). doi:10.3847/1538-4365/acf130
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  We present JWST Extragalactic Medium-band Survey, the first public medium-band imaging survey carried out using JWST/NIRCam and NIRISS. These observations use ∼2 and ∼4 μm medium-band filters (NIRCam F182M, F210M, F430M, F460M, F480M; and NIRISS F430M and F480M in parallel) over 15.6 arcmin2 in the Hubble Ultra Deep Field (UDF), thereby building on the deepest multiwavelength public data sets available anywhere on the sky. We describe our science goals, survey design, NIRCam and NIRISS image reduction methods, and describe our first data release of the science-ready mosaics, which reach 5σ point-source limits (AB mag) of ∼29.3-29.4 in 2 μm filters and ∼28.2-28.7 at 4 μm. Our chosen filters create a JWST imaging survey in the UDF that enables novel analysis of a range of spectral features potentially across the redshift range of 0.3 < z < 20, including Paschen-α, Hα+[N ii], and [O iii]+Hβ emission at high spatial resolution. We find that our JWST medium-band imaging efficiently identifies strong line emitters (medium-band colors >1 mag) across redshifts 1.5 < z < 9.3, most prominently Hα+[N ii] and [O iii]+Hβ. We present our first data release including science-ready mosaics of each medium-band image available to the community, adding to the legacy value of past and future surveys in the UDF. This survey demonstrates the power of medium-band imaging with JWST, informing future extragalactic survey strategies using JWST observations.
• Willmer, C. N., Ly, C., Kikuta, S., Kattner, S. A., Jansen, R. A., Cohen, S. H., Windhorst, R. A., Smail, I., Tompkins, S., Beacom, J. F., Cheng, C., Conselice, C. J., Frye, B. L., Koekemoer, A. M., Hathi, N., Hyun, M., Im, M., Willner, S. P., Zhao, X., , Brisken, W. A., et al. (2023). PEARLS: Near-infrared Photometry in the JWST North Ecliptic Pole Time Domain Field*. Astrophysical Journal, Supplement Series, 269(Issue 1). doi:10.3847/1538-4365/acf57d
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  We present near-infrared (NIR) ground-based Y, J, H, and K imaging obtained in the James Webb Space Telescope (JWST) North Ecliptic Pole Time Domain Field (NEP TDF) using the MMT-Magellan Infrared Imager and Spectrometer on the MMT. These new observations cover a field of approximately 230 arcmin2 in Y, H, and K, and 313 arcmin2 in J. Using Monte Carlo simulations, we estimate a 1σ depth relative to the background sky of (Y, J, H, K) = (23.80, 23.53, 23.13, 23.28) in AB magnitudes for point sources at a 95% completeness level. These observations are part of the ground-based effort to characterize this region of the sky, supplementing space-based data obtained with Chandra, NuSTAR, XMM, AstroSat, Hubble Space Telescope, and JWST. This paper describes the observations and reduction of the NIR imaging and combines these NIR data with archival imaging in the visible, obtained with the Subaru Hyper-Suprime-Cam, to produce a merged catalog of 57,501 sources. The new observations reported here, plus the corresponding multiwavelength catalog, will provide a baseline for time-domain studies of bright sources in the NEP TDF.
• Willner, S., Gim, H., del Carmen Polletta, M., Cohen, S., Willmer, C., Zhao, X., Jansen, R., Koekemoer, A., Summers, J., Windhorst, R., Coe, D., Conselice, C., Driver, S., Frye, B., Grogin, N., Marshall, M., Nonino, M., Ortiz, R., Pirzkal, N., , Robotham, A., et al. (2023). PEARLS: JWST Counterparts of Microjansky Radio Sources in the Time Domain Field. Astrophysical Journal, 958(2). doi:10.3847/1538-4357/acfdfb
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  The Time Domain Field (TDF) near the North Ecliptic Pole in JWST’s continuous-viewing zone will become a premier “blank field” for extragalactic science. JWST/NIRCam data in a 16 arcmin2 portion of the TDF identify 4.4 μm counterparts for 62 of 63 3 GHz sources with S(3 GHz) > 5 μJy. The one unidentified radio source may be a lobe of a nearby Seyfert galaxy, or it may be an infrared-faint radio source. The bulk properties of the radio-host galaxies are consistent with those found by previous work: redshifts range from 0.14-4.4 with a median redshift of 1.33. The radio emission arises primarily from star formation in ∼2/3 of the sample and from an active galactic nucleus (AGN) in ∼1/3, but just over half the sample shows evidence for an AGN either in the spectral energy distribution or by radio excess. All but three counterparts are brighter than magnitude 23 AB at 4.4 μm, and the exquisite resolution of JWST identifies correct counterparts for sources for which observations with lower angular resolution would misidentify a nearby bright source as the counterpart when the correct one is faint and red. Up to 11% of counterparts might have been unidentified or misidentified absent NIRCam observations.
• Windhorst, R. A., Cohen, S. H., Jansen, R. A., Summers, J., Tompkins, S., Conselice, C. J., Driver, S. P., Yan, H., Coe, D., Frye, B., Grogin, N., Koekemoer, A., Marshall, M. A., O’Brien, R., Pirzkal, N., Robotham, A., Ryan, R. E., Willmer, C. N., Carleton, T., , Diego, J. M., et al. (2023). JWST PEARLS. Prime Extragalactic Areas for Reionization and Lensing Science: Project Overview and First Results. Astronomical Journal, 165(Issue 1). doi:10.3847/1538-3881/aca163
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  We give an overview and describe the rationale, methods, and first results from NIRCam images of the JWST “Prime Extragalactic Areas for Reionization and Lensing Science” (PEARLS) project. PEARLS uses up to eight NIRCam filters to survey several prime extragalactic survey areas: two fields at the North Ecliptic Pole (NEP); seven gravitationally lensing clusters; two high redshift protoclusters; and the iconic backlit VV 191 galaxy system to map its dust attenuation. PEARLS also includes NIRISS spectra for one of the NEP fields and NIRSpec spectra of two high-redshift quasars. The main goal of PEARLS is to study the epoch of galaxy assembly, active galactic nucleus (AGN) growth, and First Light. Five fields—the JWST NEP Time-Domain Field (TDF), IRAC Dark Field, and three lensing clusters—will be observed in up to four epochs over a year. The cadence and sensitivity of the imaging data are ideally suited to find faint variable objects such as weak AGN, high-redshift supernovae, and cluster caustic transits. Both NEP fields have sightlines through our Galaxy, providing significant numbers of very faint brown dwarfs whose proper motions can be studied. Observations from the first spoke in the NEP TDF are public. This paper presents our first PEARLS observations, their NIRCam data reduction and analysis, our first object catalogs, the 0.9-4.5 μm galaxy counts and Integrated Galaxy Light. We assess the JWST sky brightness in 13 NIRCam filters, yielding our first constraints to diffuse light at 0.9-4.5 μm. PEARLS is designed to be of lasting benefit to the community.
• Witstok, J., Shivaei, I., Smit, R., Maiolino, R., Carniani, S., Curtis-Lake, E., Ferruit, P., Arribas, S., Bunker, A. J., Cameron, A. J., Charlot, S., Chevallard, J., Curti, M., de Graaff, A., D’Eugenio, F., Giardino, G., Looser, T. J., Rawle, T., Rodríguez del Pino, B., , Willott, C., et al. (2023). Carbonaceous dust grains seen in the first billion years of cosmic time. Nature, 621(Issue 7978). doi:10.1038/s41586-023-06413-w
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  Large dust reservoirs (up to approximately 108 M ⊙) have been detected1–3 in galaxies out to redshift z ≃ 8, when the age of the Universe was only about 600 Myr. Generating substantial amounts of dust within such a short timescale has proven challenging for theories of dust formation4,5 and has prompted the revision of the modelling of potential sites of dust production6–8, such as the atmospheres of asymptotic giant branch stars in low-metallicity environments, supernova ejecta and the accelerated growth of grains in the interstellar medium. However, degeneracies between different evolutionary pathways remain when the total dust mass of galaxies is the only available observable. Here we report observations of the 2,175 Å dust attenuation feature, which is well known in the Milky Way and galaxies at z ≲ 3 (refs. 9–11), in the near-infrared spectra of galaxies up to z ≃ 7, corresponding to the first billion years of cosmic time. The relatively short timescale implied for the formation of carbonaceous grains giving rise to this feature12 suggests a rapid production process, possibly in Wolf–Rayet stars or supernova ejecta.
• Yan, H., Cohen, S. H., Windhorst, R. A., Jansen, R. A., Ma, Z., Beacom, J. F., Ling, C., Cheng, C., Huang, J. S., Grogin, N. A., Willner, S. P., Yun, M., Hammel, H. B., Milam, S. N., Conselice, C. J., Driver, S. P., Frye, B., Marshall, M. A., Koekemoer, A., , Willmer, C. N., et al. (2023). JWST's PEARLS: Bright 1.5-2.0 μm Dropouts in the Spitzer/IRAC Dark Field. Astrophysical Journal Letters, 942(Issue 1). doi:10.3847/2041-8213/aca974
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  Using the first epoch of four-band NIRCam observations obtained by the James Webb Space Telescope (JWST) Prime Extragalactic Areas for Reionization and Lensing Science Program in the Spitzer IRAC Dark Field, we search for F150W and F200W dropouts. In 14.2 arcmin2, we have found eight F150W dropouts and eight F200W dropouts, all brighter than 27.5 mag (the brightest being ∼24 mag) in the band to the red side of the break. As they are detected in multiple bands, these must be real objects. Their nature, however, is unclear, and characterizing their properties is important for realizing the full potential of JWST. If the observed color decrements are due to the Lyman break, these objects should be at z ≲11.7 and z ≳15.4, respectively. The color diagnostics show that at least four F150W dropouts are far away from the usual contaminators encountered in dropout searches (red galaxies at much lower redshifts or brown dwarf stars). While the diagnostics of the F200W dropouts are less certain due to the limited number of passbands, at least one of them is likely not a known type of contaminant, and the rest are consistent with either high-redshift galaxies with evolved stellar populations or old galaxies at z ≈ 3-8. If a significant fraction of our dropouts are indeed at z ≳12, we have to face the severe problem of explaining their high luminosities and number densities. Spectroscopic identifications of such objects are urgently needed.
• Yan, H., Ma, Z., Sun, B., Wang, L., Kelly, P., Diego, J., Cohen, S., Windhorst, R., Jansen, R., Grogin, N., Beacom, J., Conselice, C., Driver, S., Frye, B., Coe, D., Marshall, M., Koekemoer, A., Willmer, C., Robotham, A., , Summers, J., et al. (2023). JWST's PEARLS: Transients in the MACS J0416.1−2403 Field. Astrophysical Journal, Supplement Series, 2(43). doi:10.3847/1538-4365/ad0298
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  With its unprecedented sensitivity and spatial resolution, the James Webb Space Telescope (JWST) has opened a new window for time-domain discoveries in the infrared. Here we report observations in the only field that has received four epochs (spanning 126 days) of JWST NIRCam observations in Cycle 1. This field is toward MACS J0416.1−2403, which is a rich galaxy cluster at redshift z = 0.4 and is one of the Hubble Frontier Fields. We have discovered 14 transients from these data. Twelve of these transients happened in three galaxies (with z = 0.94, 1.01, and 2.091) crossing a lensing caustic of the cluster, and these transients are highly magnified by gravitational lensing. These 12 transients are likely of a similar nature to those previously reported based on the Hubble Space Telescope (HST) data in this field, i.e., individual stars in the highly magnified arcs. However, these 12 could not have been found by HST because they were too red and too faint. The other two transients are associated with background galaxies (z = 2.205 and 0.7093) that are only moderately magnified, and they are likely supernovae. They indicate a demagnified supernova surface density, when monitored at a time cadence of a few months to a ∼3-4 μm survey limit of AB ∼28.5 mag, of ∼0.5 arcmin−2 integrated to z ≈ 2. This survey depth is beyond the capability of HST but can be easily reached by JWST.
• Zavala, J. A., Zavala, J., Buat, V., Buat, V., Casey, C., Casey, C. M., Finkelstein, S. L., Finkelstein, S., Burgarella, D., Burgarella, D., Bagley, M., Ciesla, L., Ciesla, L., Daddi, E., Daddi, E., Dickinson, M., Ferguson, H., Ferguson, H., Franco, M., , Jiménez-Andrade, E. F., et al. (2023). Dusty Starbursts Masquerading as Ultra-high Redshift Galaxies in JWST CEERS Observations. Astrophysical Journal Letters, 943(2). doi:10.3847/2041-8213/acacfe
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  Lyman-break galaxy (LBG) candidates at z ≳ 10 are rapidly being identified in James Webb Space Telescope (JWST)/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources are expected to drop out in the bluer filters while being well detected in redder filters. However, here we show that dust-enshrouded star-forming galaxies at lower redshifts (z ≲ 7) may also mimic the near-infrared (near-IR) colors of z > 10 LBGs, representing potential contaminants in LBG candidate samples. First, we analyze CEERS-DSFG-1, a NIRCam dropout undetected in the F115W and F150W filters but detected at longer wavelengths. Combining the JWST data with (sub)millimeter constraints, including deep NOEMA interferometric observations, we show that this source is a dusty star-forming galaxy (DSFG) at z ≈ 5.1. We also present a tentative 2.6σ SCUBA-2 detection at 850 μm around a recently identified z ≈ 16 LBG candidate in the same field and show that, if the emission is real and associated with this candidate, the available photometry is consistent with a z ∼ 5 dusty galaxy with strong nebular emission lines despite its blue near-IR colors. Further observations on this candidate are imperative to mitigate the low confidence of this tentative submillimeter emission and its positional uncertainty. Our analysis shows that robust (sub)millimeter detections of NIRCam dropout galaxies likely imply z ∼ 4-6 redshift solutions, where the observed near-IR break would be the result of a strong rest-frame optical Balmer break combined with high dust attenuation and strong nebular line emission, rather than the rest-frame UV Lyman break. This provides evidence that DSFGs may contaminate searches for ultra-high redshift LBG candidates from JWST observations.
• Cheng, C., Yan, H., Huang, J. S., Willmer, C. N., Ma, Z., & Orellana-González, G. (2022). Properties of Host Galaxies of Submillimeter Sources as Revealed by JWST Early Release Observations in SMACS J0723.3-7327. Astrophysical Journal Letters, 936(Issue 2). doi:10.3847/2041-8213/ac8d08
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  Using the 0.9-4.4 μm imaging data from the James Webb Space Telescope (JWST) early release observation in the SMACS J0723.3-7327 galaxy cluster field, we discuss the properties of three submillimeter galaxies (SMGs) detected by the Atacama Large Millimeter/submillimeter Array Array. These sources are magnified by 1.4-2.1 × due to gravitational lensing. This is the first time that submillimeter galaxy hosts are resolved in the rest-frame near-infrared (NIR). One source was previously undetected by Hubble Space Telescope, while the remaining two are disk galaxies with Sérsic indices of ∼0.9 and star formation rates on or just below the star formation “main sequence.” Their submillimeter emission originates from the inner parts of the hosts, suggesting that their dust contents are concentrated toward the center. The host half-light radii measured in the rest-frame NIR are ∼1.5 × smaller than those measured in the rest-frame optical, consistent with a concentrated dust distribution. The more severe extinction that optical light suffers toward the center makes it seemingly less concentrated. Therefore, we expect that the optically based determination of the stellar mass distribution within host galaxies could still be severely biased by dust. Interestingly, these two disk galaxies are dramatically different in their outer regions, with one being star forming and the other being quiescent. Upcoming JWST observations of statistically significant samples of SMGs will allow us to understand the correlation between the dusty star-forming regions and their hosts.
• Finkelstein, S. L., Bagley, M. B., Haro, P. A., Dickinson, M., Ferguson, H. C., Kartaltepe, J. S., Papovich, C., Burgarella, D., Kocevski, D. D., Huertas-Company, M., Iyer, K. G., Koekemoer, A. M., Larson, R. L., Pérez-González, P. G., Rose, C., Tacchella, S., Wilkins, S. M., Chworowsky, K., Medrano, A., , Morales, A. M., et al. (2022). A Long Time Ago in a Galaxy Far, Far Away: A Candidate z ~ 12 Galaxy in Early JWST CEERS Imaging. Astrophysical Journal Letters, 940(Issue 2). doi:10.3847/2041-8213/ac966e
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  We report the discovery of a candidate galaxy with a photo-z of z ~ 12 in the first epoch of the James Webb Space Telescope (JWST) Cosmic Evolution Early Release Science Survey. Following conservative selection criteria, we identify a source with a robust zphot = 11.8-0.2+0.3 (1σ uncertainty) with mF200W = 27.3 and ≥7σ detections in five filters. The source is not detected at λ < 1.4 μm in deep imaging from both Hubble Space Telescope (HST) and JWST and has faint ~3σ detections in JWST F150W and HST F160W, which signal a Lyα break near the red edge of both filters, implying z ~ 12. This object (Maisie's Galaxy) exhibits F115W-F200W > 1.9 mag (2σ lower limit) with a blue continuum slope, resulting in 99.6% of the photo-z probability distribution function favoring z > 11. All data-quality images show no artifacts at the candidate's position, and independent analyses consistently find a strong preference for z > 11. Its colors are inconsistent with Galactic stars, and it is resolved (rh = 340 ± 14 pc). Maisie's Galaxy has log M∗/M⊙ ~ 8.5 and is highly star-forming (log sSFR~-8.2 yr-1), with a blue rest- UV color (β~-2.5) indicating little dust, though not extremely low metallicity. While the presence of this source is in tension with most predictions, it agrees with empirical extrapolations assuming UV luminosity functions that smoothly decline with increasing redshift. Should follow-up spectroscopy validate this redshift, our universe was already aglow with galaxies less than 400 Myr after the Big Bang.
• Sun, F., Egami, E., Pirzkal, N., Rieke, M., Boyer, M., Correnti, M., Gennaro, M., Girard, J., Greene, T. P., Kelly, D., Koekemoer, A. M., Leisenring, J., Misselt, K., Nikolov, N., Roellig, T. L., Stansberry, J., Williams, C. C., & Willmer, C. N. (2022). First Peek with JWST/NIRCam Wide-field Slitless Spectroscopy: Serendipitous Discovery of a Strong [O iii]/H α Emitter at z = 6.11. Astrophysical Journal Letters, 936(Issue 1). doi:10.3847/2041-8213/ac8938
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  We report the serendipitous discovery of an [O iii] λ λ4959/5007 and Hα line emitter in the Epoch of Reionization (EoR) with the James Webb Space Telescope (JWST) commissioning data taken in the NIRCam wide-field slitless spectroscopy (WFSS) mode. Located 1/455″ away from the flux calibrator P330-E, this galaxy exhibits bright [O iii] λ λ4959/5007 and Hα lines detected at 3.7σ, 9.9σ, and 5.7σ, respectively, with a spectroscopic redshift of z = 6.112 ± 0.001. The total Hβ+[O iii] equivalent width is 664 ± 98 Å (454 ± 78 Å from the [O iii] λ5007 line). This provides direct spectroscopic evidence for the presence of strong rest-frame optical lines (Hβ+[O iii] and Hα) in EoR galaxies as inferred previously from the analyses of the Spitzer/IRAC spectral energy distributions (SEDs). Two spatial and velocity components are identified in this source, possibly indicating that this system is undergoing a major merger, which might have triggered the ongoing starburst with strong nebular emission lines over a timescale of 1/42 Myr, as our SED modeling suggests. The tentative detection of He ii λ4686 line (1.9σ), if real, may indicate the existence of very young and metal-poor star-forming regions with a hard UV radiation field. Finally, this discovery demonstrates the power and readiness of the JWST/NIRCam WFSS mode, and marks the beginning of a new era for extragalactic astronomy, in which EoR galaxies can be routinely discovered via blind slitless spectroscopy through the detection of rest-frame optical emission lines.
• Williams, C. C., Alberts, S., Spilker, J. S., Noble, A. G., Stefanon, M., Willmer, C. N., Bezanson, R., Narayanan, D., & Whitaker, K. E. (2022). ALMA Measures Molecular Gas Reservoirs Comparable to Field Galaxies in a Low-mass Galaxy Cluster at z = 1.3. Astrophysical Journal, 929(Issue 1). doi:10.3847/1538-4357/ac58fa
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  We report the serendipitous discovery of an overdensity of CO emitters in an X-ray-identified cluster (Log10 M halo/M ⊙ ∼13.6 at z = 1.3188) using ALMA. We present spectroscopic confirmation of six new cluster members exhibiting CO(2-1) emission, adding to two existing optical/IR spectroscopic members undetected in CO. This is the lowest-mass cluster to date at z > 1 with molecular gas measurements, bridging the observational gap between galaxies in the more extreme, well-studied clusters (Log10 M halo/M ⊙ 3 14) and those in group or field environments at cosmic noon. The CO sources are concentrated on the sky (within ∼1 arcmin diameter) and phase space analysis indicates the gas resides in galaxies already within the cluster environment. We find that CO sources sit in similar phase space as CO-rich galaxies in more massive clusters at similar redshifts (have similar accretion histories) while maintaining field-like molecular gas reservoirs, compared to scaling relations. This work presents the deepest CO survey to date in a galaxy cluster at z > 1, uncovering gas reservoirs down to MH2>1.6×1010 M ⊙ (5σ at 50% primary beam). Our deep limits rule out the presence of gas content in excess of the field scaling relations; however, combined with literature CO detections, cluster gas fractions in general appear systematically high, on the upper envelope or above the field. This study is the first demonstration that low-mass clusters at z ∼1-2 can host overdensities of CO emitters with surviving gas reservoirs, in line with the prediction that quenching is delayed after first infall while galaxies consume the gas bound to the disk.
• Cheng, C., Huang, J., Willmer, C. N., Zhang, H., Ashby, M. L., Xu, H., Sawicki, M., Arnouts, S., Gwyn, S., Desprez, G., Coupon, J., Golob, A., Liang, P., Cao, T., Shi, Y., Jin, G., He, C., Wu, S., Li, Z., , Sophia Dai, Y., et al. (2021). "Searching for Low-redshift Faint Galaxies with MMT/Hectospec". apjs, 256(1), 4.
• Zhao, X., Civano, F., Fornasini, F., Alexander, D., Cappelluti, N., Chen, C., Cohen, S., Elvis, M., Gandhi, P., Grogin, N., Hickox, R., Jansen, R., Koekemoer, A., Lanzuisi, G., Maksym, W., Masini, A., Rosario, D., Ward, M., Willmer, C., & Windhorst, R. (2021). "The NuSTAR extragalactic survey of the James Webb Space Telescope North Ecliptic Pole time-domain field". mnras, 508(4), 5176-5195.
• Hainline, K. N., Hviding, R. E., Rieke, M., Shivaei, I., Endsley, R., Curtis-Lake, E., Smit, R., Williams, C. C., Alberts, S., K, B., Bunker, A. J., Egami, E., Maseda, M. V., Tacchella, S., & Willmer, C. N. (2020). "Simulating JWST/NIRCam Color Selection of High-redshift Galaxies". apj, 892(2), 125.
• Burchett, J. N., Butsky, I., Tremmel, M., Bordoloi, R., Bryan, G. L., Cai, Z., Canning, R. E., Chen, H., Coil, A. L., Fielding, D., Fumagalli, M., Johnson, S. D., Khaire, V., Lee, K., Lehner, N., Mandelker, N., O'meara, J. M., Nelson, D., Oppenheimer, B. D., , Postman, M., et al. (2019). Ultraviolet Perspectives on Diffuse Gas in the Largest Cosmic Structures. Bulletin of the American Astronomical Society, 51(3).
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  In this White Paper, we highlight key science cases where UV spectroscopy will provide unique insights into the most massive structures in the Universe, and we discuss how current (HST/COS) and future (LUVOIR) missions can deliver transformative understanding of galaxy evolution, galaxy cluster physics, and gas within the Cosmic Web.
• Burchett, J. N., Tripp, T. M., Prochaska, J. X., Werk, J. K., Tumlinson, J., Howk, J. C., Willmer, C. N., Lehner, N., Meiring, J. D., Bowen, D. V., Bordoloi, R., Peeples, M. S., Jenkins, E. B., O'Meara, J. M., Tejos, N., & Katz, N. (2019). The COS Absorption Survey of Baryon Harbors (CASBaH): Warm-Hot Circumgalactic Gas Reservoirs Traced by Ne VIII Absorption. apjl, 877(2), L20.
• Prochaska, J. X., Burchett, J. N., Tripp, T. M., Werk, J. K., Willmer, C. N., Howk, J. C., Lange, S., Tejos, N., Meiring, J. D., Tumlinson, J., Lehner, N., Ford, A. B., & Dav{'e}, R. (2019). The COS Absorption Survey of Baryon Harbors: The Galaxy Database and Cross-correlation Analysis of O VI Systems. apjs, 243(2), 24.
• Rieke, M., Arribas, S., Bunker, A., Charlot, S., Finkelstein, S., Maiolino, R., Robertson, B., Willott, C., Windhorst, R., Eisenstein, D., Nelson, E., Tacchella, S., Egami, E., Endsley, R., Frye, B., Hainline, K., Hviding, R., Rieke, G., Williams, C., , Willmer, C., et al. (2019). JWST GTO/ERS Deep Surveys. baas, 51(3), 45.
• Watson, C., Tran, K., Tomczak, A., Alcorn, L., Salazar, I. V., Gupta, A., Momcheva, I., Papovich, C., Dokkum, P., Brammer, G., Lotz, J., & Willmer, C. N. (2019). Galaxy Merger Fractions in Two Clusters at ztextbackslashsim 2 Using the Hubble Space Telescope. apj, 874(1), 63.
• Windhorst, R., Alpaslan, M., Andrews, S., Ashcraft, T., Broadhurst, T., Coe, D., Conselice, C., Cohen, S., Diego, J., Dijkstra, M., Driver, S., Duncan, K., Finkelstein, S., Frye, B., Griffiths, A., Grogin, N., Hathi, N., Hopkins, A., Jansen, R., , Joshi, B., et al. (2019). On the observability of individual Population III stars and their stellar-mass black hole accretion disks through cluster caustic transits. baas, 51(3), 449.
• Zhou, R., Cooper, M. C., Newman, J. A., Ashby, M. L., Aird, J., Conselice, C. J., Davis, M., Dutton, A. A., Faber, S., Fang, J. J., Fazio, G., Guhathakurta, P., Kocevski, D., Koo, D. C., {Nand, r. K., Phillips, A. C., Rosario, D. J., Schlafly, E. F., Trump, J. R., , Weiner, B., et al. (2019). Deep ugrizY imaging and DEEP2/3 spectroscopy: a photometric redshift testbed for LSST and public release of data from the DEEP3 Galaxy Redshift Survey. mnras, 488(4), 4565-4584.
• Burchett, J., Tripp, T., Wang, Q., Willmer, C., Bowen, D., & Jenkins, E. (2018). Warm-hot gas in X-ray bright galaxy clusters and the H I-deficient circumgalactic medium in dense environments. \mnras, 475, 2067-2085.
• Cheng, C., Ibar, E., Hughes, T., Villanueva, V., Leiton, R., Orellana, G., Mu{\~noz, A. A., Lu, N., Xu, C., Willmer, C., Huang, J., Cao, T., Yang, C., Xue, Y., & Torstensson, K. (2018). VALES - IV. Exploring the transition of star formation efficiencies between normal and starburst galaxies using APEX/SEPIA Band-5 and ALMA at low redshift. \mnras, 475, 248-256.
• Maksym, W., Civano, F., MacLeod, C., Jansen, R., Windhorst, R., Ashcraft, T., Jones, V., Cohen, S., Koekemoer, A., Grogin, N., Cappelluti, N., Willmer, C., Elvis, M., Fazio, G., Ashby, M., Hasinger, G., Cotton, B., Condon, J., Brisken, W., & Perley, R. (2018). A Strong X-ray Flare from a Likely z$\gt$1 AGN Adjoining the JWST NEP-TDF. The Astronomer's Telegram, 11906.
• Simm, T., Buchner, J., Merloni, A., Nandra, K., Shen, Y., Erben, T., Coil, A., Willmer, C., & Schneider, D. (2018). Dramatic X-ray spectral variability of a Compton-thick type-1 QSO at z \tilde 1. \mnras, 480, 4912-4917.
• Williams, C., Curtis-Lake, E. .., Hainline, K., Chevallard, J., Robertson, B., Charlot, S., Endsley, R., Stark, D., Willmer, C., Alberts, S., Amorin, R., Arribas, S., Baum, S., Bunker, A., Carniani, S., Crandall, S., Egami, E., Eisenstein, D., Ferruit, P., , Husemann, B., et al. (2018). The JWST Extragalactic Mock Catalog: Modeling Galaxy Populations from the UV through the Near-IR over 13 Billion Years of Cosmic History. \apjs, 236, 33.
• Willmer, C. (2018). The Absolute Magnitude of the Sun in Several Filters. \apjs, 236, 47.
• Cheng, C., Ibar, E., Hughes, T. M., Villanueva, V., Leiton, R., Orellana, G., Muñoz Arancibia, A., Lu, N., Xu, C. K., Willmer, C. N., Huang, J., Cao, T., Yang, C., Xue, Y. Q., & Torstensson, K. (2017). VALES – IV. Exploring the transition of star formation efficiencies between normal and starburst galaxies using APEX/SEPIA Band-5 and ALMA at low redshift. Monthly Notices of the Royal Astronomical Society, 475(1), 248-256. doi:10.1093/mnras/stx3183
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  In this work, we present new the Swedish-ESO PI receiver for the Atacama Pathfinder Experiment APEX/SEPIA Band-5 observations targeting the CO (J = 2-1) emission line of 24 Herschel-detected galaxies at Ζ = 0.1-0.2. Combining this sample with our recent new Valparáiso ALMA Line Emission Survey (VALES), we investigate the star formation efficiencies [SFEs=star formation rate (SFR)/MH2] of galaxies at low redshift. We find the SFE of our sample bridges the gap between normal star-forming galaxies and Ultra-Luminous Infrared Galaxies (ULIRGs), which are thought to be triggered by different star formation modes. Considering the SFE' as the SFR and the L'CO ratio, our data show a continuous and smooth increment as a function of infrared luminosity (or star formation rate) with a scatter about 0.5 dex, instead of a steep jump with a bimodal behaviour. This result is due to the use of a sample with a much larger range of sSFR/sSFRms using LIRGs, with luminosities covering the range between normal and ULIRGs. We conclude that the main parameters controlling the scatter of the SFE in star-forming galaxies are the systematic uncertainty of the αCO conversion factor, the gas fraction, and physical size.
• Devereux, N., Willner, S. P., Ashby, M. L., Willmer, C. N., & Hriljac, P. (2017). Erratum: “Nearby Galaxies in the 2 μm All Sky Survey. I. K-Band Luminosity Functions” (2009, ApJ, 702, 955). The Astrophysical Journal, 844(2), 173. doi:10.3847/1538-4357/aa7b32
• Lee-Brown, D., Rudnick, G., Momcheva, I., Papovich, C., Lotz, J., Tran, K., Henke, B., Willmer, C., Brammer, G., Brodwin, M., Dunlop, J., & Farrah, D. (2017). "The Ages of Passive Galaxies in a z = 1.62 Protocluster". apj, 844, 43.
• Rudnick, G., Hodge, J., Walter, F., Momcheva, I., Tran, K., Papovich, C., Cunha, E., Decarli, R., Saintonge, A., Willmer, C., Lotz, J., & Lentati, L. (2017). "Deep CO(1-0) Observations of z = 1.62 Cluster Galaxies with Substantial Molecular Gas Reservoirs and Normal Star Formation Efficiencies". apj, 849, 27.
• Amorin, R., Barro, G., Cooper, M. C., Dave, R., Dekel, A., Faber, S. M., Forbes, J. C., Guhathakurta, P., Guo, Y., Hathi, N. P., Kirby, E. N., Koekemoer, A. M., Koo, D. C., Lin, L., Lu, Y., Newman, J. A., Perez-gonzalez, P. G., Primack, J. R., Rafelski, M., , Rosario, D. J., et al. (2016). STELLAR MASS-GAS-PHASE METALLICITY RELATION at 0.5 ≤ z ≤ 0.7: A POWER LAW with INCREASING SCATTER TOWARD the LOW-MASS REGIME. The Astrophysical Journal, 822(2), 103-103. doi:10.3847/0004-637x/822/2/103
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  NSF [AST-0808133, AST-1405962]; NASA through a grant from the Space Telescope Science Institute [HST-GO-12060, HST-AR-13891]; NASA [NAS 5-26555]; NASA through Hubble Fellowship - Space Telescope Science Institute [51330]; ISF [24/12]; I-CORE Program of the PBC ISF grant [1829/12]; Spanish MINECO [AYA2012-31277]; [HST-AR-13909]
• Bordoloi, R., Burchett, J. N., Katz, N., O'meara, J. M., Prochaska, J. X., Tripp, T. M., Tumlinson, J., Werk, J. K., & Willmer, C. N. (2016). A DEEP SEARCH FOR FAINT GALAXIES ASSOCIATED WITH VERY LOW REDSHIFT C iv ABSORBERS. III. THE MASS- AND ENVIRONMENT-DEPENDENT CIRCUMGALACTIC MEDIUM. The Astrophysical Journal, 832(2), 124. doi:10.3847/0004-637x/832/2/124
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  NASA from the Space Telescope Science Institute [HST-GO-11741, HST-GO-11598, HST-GO-12248, HST-AR-13894]; NASA [NAS5-26555]; Alfred P. Sloan Foundation; National Science Foundation; U.S. Department of Energy Office of Science; University of Arizona; Brazilian Participation Group; Brookhaven National Laboratory; Carnegie Mellon University; University of Florida; French Participation Group; German Participation Group; Harvard University; Instituto de Astrofisica de Canarias; Michigan State/Notre Dame/JINA Participation Group; Johns Hopkins University; Lawrence Berkeley National Laboratory; Max Planck Institute for Astrophysics; Max Planck Institute for Extraterrestrial Physics; New Mexico State University; New York University; Ohio State University; Pennsylvania State University; University of Portsmouth; Princeton University; Spanish Participation Group; University of Tokyo; University of Utah; Vanderbilt University; University of Virginia; University of Washington; Yale University
• Guo, Y., Koo, D., Lu, Y., Forbes, J., Rafelski, M., Trump, J., Barro, G., Faber, S., Hathi, N., Yesuf, H., Cooper, M., Dekel, A., Guhathakurta, P., Kirby, E., Koekemoer, A., Lin, L., Newman, J., Primack, J., Rosario, D., , Willmer, C., et al. (2016). STELLAR MASS-GAS-PHASE METALLICITY RELATION at 0.5 ≤ z ≤ 0.7: A POWER LAW with INCREASING SCATTER TOWARD the LOW-MASS REGIME. Astrophysical Journal, 822(2). doi:10.3847/0004-637X/822/2/103
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  We present the stellar mass (M∗)gas-phase metallicity relation (MZR) and its scatter at intermediate redshifts (0.5 ≤ z ≤ 0.7) for 1381 field galaxies collected from deep spectroscopic surveys. The star formation rate (SFR) and color at a given M∗ of this magnitude-limited (R ≳ 24 AB) sample are representative of normal starforming galaxies. For masses below 109 Mo, our sample of 237 galaxies is ∼10 times larger than those in previous studies beyond the local universe. This huge gain in sample size enables superior constraints on the MZR and its scatter in the low-mass regime. We find a power-law MZR at 108 Mo < M∗ < 1011 Mo: 12 + log (O/H) = (5.83 ± 0.19) +(0.30 ± 0.02) log (M∗/Mo). At 109 Mo < M∗ < 1010.5 Mo, our MZR shows agreement with others measured at similar redshifts in the literature. Our power-law slope is, however, shallower than the extrapolation of the MZRs of others to masses below 109 Mo. The SFR dependence of the MZR in our sample is weaker than that found for local galaxies (known as the fundamental metallicity relation). Compared to a variety of theoretical models, the slope of our MZR for low-mass galaxies agrees well with predictions incorporating supernova energy-driven winds. Being robust against currently uncertain metallicity calibrations, the scatter of the MZR serves as a powerful diagnostic of the stochastic history of gas accretion, gas recycling, and star formation of low-mass galaxies. Our major result is that the scatter of our MZR increases as Mo decreases. Our result implies that either the scatter of the baryonic accretion rate (δṀ? ) or the scatter of the M∗-Mhalo relation (δSHMR) increases as M∗ decreases. Moreover, our measure of scatter at z = 0.7 appears consistent with that found for local galaxies. This lack of redshift evolution constrains models of galaxy evolution to have both δṀ and δSHMR remain unchanged from z = 0.7 to z = 0.
• Willmer, C. N., Perez, J. M., Hoyos, C., Diaz, A. I., & Koo, D. C. (2016). Direct determination of oxygen abundances in line-emitting star-forming galaxies at intermediate redshift. Monthly Notices of the Royal Astronomical Society, 455(3), 3359-3366. doi:http://dx.doi.org/10.1093/mnras/stv1949
• {Burchett}, J., {Tripp}, T., {Bordoloi}, R., {Werk}, J., {Prochaska}, J., {Tumlinson}, J., {Willmer}, C., {O'Meara}, J., , N. (2016). "{A Deep Search for Faint Galaxies Associated with Very Low Redshift C iv Absorbers. III. The Mass- and Environment-dependent Circumgalactic Medium}". apj, 832, 124.
• {Guo}, Y., {Koo}, D., {Lu}, Y., {Forbes}, J., {Rafelski}, M., {Trump}, J., {Amor{'{i}}n}, R., {Barro}, G., {Dav{'e}}, R., {Faber}, S., {Hathi}, N., {Yesuf}, H., {Cooper}, M., {Dekel}, A., {Guhathakurta}, P., {Kirby}, E., {Koekemoer}, A., {P{'e}rez-Gonz{'a}lez}, P., {Lin}, L., , {Newman}, J., et al. (2016). "{Stellar Mass-Gas-phase Metallicity Relation at 0.5 {le} z {le} 0.7: A Power Law with Increasing Scatter toward the Low-mass Regime}". apj, 822, 103.
• Bordoloi, R., Burchett, J. N., Katz, N., O'meara, J. M., Prochaska, J. X., Tripp, T. M., Tumlinson, J., Werk, J. K., & Willmer, C. N. (2015). A DEEP SEARCH FOR FAINT GALAXIES ASSOCIATED WITH VERY LOW-REDSHIFT C iv ABSORBERS. II. PROGRAM DESIGN, ABSORPTION-LINE MEASUREMENTS, AND ABSORBER STATISTICS. The Astrophysical Journal, 815(2), 91. doi:10.1088/0004-637x/815/2/91
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  To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium (CGM), we have conducted a blind survey for C IV absorption systems in 89 QSO sightlines observed with the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS). We have identified 42 absorbers at z < 0.16, comprising the largest uniform blind sample size to date in this redshift range. Our measurements indicate an increasing C IV absorber number density per comoving path length (dN/dX = 7.5 +/- 1.1) and modestly increasing mass density relative to the critical density of the Universe (Omega(C IV) = 10.0 +/- 1.5 x 10^-8 ) from z ~ 1.5 to the present epoch, consistent with predictions from cosmological hydrodynamical simulations. Furthermore, the data support a functional form for the column density distribution function that deviates from a single power-law, also consistent with independent theoretical predictions. As the data also probe heavy element ions in addition to C IV at the same redshifts, we identify, measure, and search for correlations between column densities of these species where components appear aligned in velocity. Among these ion-ion correlations, we find evidence for tight correlations between C II and Si II, C II and Si III, and C IV and Si IV, suggesting that these pairs of species arise in similar ionization conditions. However, the evidence for correlations decreases as the difference in ionization potential increases. Finally, when controlling for observational bias, we find only marginal evidence for a correlation (86.8% likelihood) between the Doppler line width b(C IV) and column density N(C IV).
• Chatterjee, S., Newman, J. A., Jeltema, T., Myers, A. D., Aird, J., Bundy, K., Conselice, C., Cooper, M., Laird, E., Nandra, K., & Willmer, C. (2015). X-RAY EMISSION in NON-AGN GALAXIES at z ≃ 1. Astrophysical Journal, 806(Issue 1). doi:10.1088/0004-637x/806/1/136
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  Using data from the DEEP2 galaxy redshift survey and the All Wavelength Extended Groth Strip International Survey we obtain stacked X-ray maps of galaxies at 0.7 ≤ z ≤ 1.0 as a function of stellar mass. We compute the total X-ray counts of these galaxies and show that in the soft band (0.52 kev) there exists a significant correlation between galaxy X-ray counts and stellar mass at these redshifts. The best-fit relation between X-ray counts and stellar mass can be characterized by a power law with a slope of 0.58 ±0.1. We do not find any correlation between stellar mass and X-ray luminosities in the hard (27 kev) and ultra-hard (47 kev) bands. The derived hardness ratios of our galaxies suggest that the X-ray emission is degenerate between two spectral models, namely point-like power-law emission and extended plasma emission in the interstellar medium. This is similar to what has been observed in low redshift galaxies. Using a simple spectral model where half of the emission comes from power-law sources and the other half from the extended hot halo we derive the X-ray luminosities of our galaxies. The soft X-ray luminosities of our galaxies lie in the range 10398 ×1040 erg s-1 Dividing our galaxy sample by the criteria U-B> 1, we find no evidence that our results for X-ray scaling relations depend on optical color.
• {Burchett}, J., {Tripp}, T., {Prochaska}, J., {Werk}, J., {Tumlinson}, J., {O'Meara}, J., {Bordoloi}, R., {Katz}, N., , C. (2015). "A Deep Search For Faint Galaxies Associated With Very Low-redshift C IV Absorbers. II. Program Design, Absorption-line Measurements, and Absorber Statistics". apj, 815, 91.
• {Chatterjee}, S., {Newman}, J., {Jeltema}, T., {Myers}, A., {Aird}, J., {Bundy}, K., {Conselice}, C., {Cooper}, M., {Laird}, E., {Nandra}, K., , C. (2015). "X-Ray Emission in Non-AGN Galaxies at z ~ 1". apj, 806, 136.
• {Chatterjee}, S., {Newman}, J., {Jeltema}, T., {Myers}, A., {Aird}, J., {Coil}, A., {Cooper}, M., {Finoguenov}, A., {Laird}, E., {Montero-Dorta}, A., {Nandra}, K., {Willmer}, C., , R. (2015). "X-ray Surface Brightness Profiles of Active Galactic Nuclei in the Extended Groth Strip: Implications for AGN Feedback". pasp, 127, 716-725.
• {Nandra}, K., {Laird}, E., {Aird}, J., {Salvato}, M., {Georgakakis}, A., {Barro}, G., {Perez-Gonzalez}, P., {Barmby}, P., {Chary}, R., {Coil}, A., {Cooper}, M., {Davis}, M., {Dickinson}, M., {Faber}, S., {Fazio}, G., {Guhathakurta}, P., {Gwyn}, S., {Hsu}, L., {Huang}, J., , {Ivison}, R., et al. (2015). "AEGIS-X: Deep Chandra Imaging of the Central Groth Strip". apjs, 220, 10.
• Dai, Y. S., Elvis, M., Bergeron, J., Fazio, G. G., Huang, J., Wilkes, B. J., Willmer, C. N., Omont, A., & Papovich, C. (2014). Mid-infrared-selected Quasars. I. Virial Black Hole Mass and Eddington Ratios. apj, 791, 113.
• Alexander, D. M., Bournaud, F., Coil, A. L., Cooper, M. C., Daddi, E., Dickinson, M., Elbaz, D., Faber, S. M., Frayer, D. T., Hwang, H. S., Juneau, S., Kartaltepe, J. S., Kocevski, D. D., Laird, E. S., Magnelli, B., Monkiewicz, J. A., Mullaney, J. R., Nandra, K., Newman, J. A., , Rosario, D. J., et al. (2013). Widespread and Hidden Active Galactic Nuclei in Star-Forming Galaxies at Redshift > 0.3. The Astrophysical Journal, 764(2), 176. doi:10.1088/0004-637x/764/2/176
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  We characterize the incidence of active galactic nuclei (AGNs) in 0.3 < z < 1 star-forming galaxies by applying multi-wavelength AGN diagnostics (X-ray, optical, mid-infrared, radio) to a sample of galaxies selected at 70 μm from the Far-Infrared Deep Extragalactic Legacy survey (FIDEL). Given the depth of FIDEL, we detect "normal" galaxies on the specific star formation rate (sSFR) sequence as well as starbursting systems with elevated sSFR. We find an overall high occurrence of AGN of 37% ± 3%, more than twice as high as in previous studies of galaxies with comparable infrared luminosities and redshifts but in good agreement with the AGN fraction of nearby (0.05 < z < 0.1) galaxies of similar infrared luminosities. The more complete census of AGNs comes from using the recently developed Mass-Excitation (MEx) diagnostic diagram. This optical diagnostic is also sensitive to X-ray weak AGNs and X-ray absorbed AGNs, and reveals that absorbed active nuclei reside almost exclusively in infrared-luminous hosts. The fraction of galaxies hosting an AGN appears to be independent of sSFR and remains elevated both on the sSFR sequence and above. In contrast, the fraction of AGNs that are X-ray absorbed increases substantially with increasing sSFR, possibly due to an increased gas fraction and/or gas density in the host galaxies.
• Aubourg, E., Bautista, J. E., Busca, N. G., Escoffier, S., Goff, J. M., Hamilton, J. C., Labatie, A., Manera, M., Mcbride, C. K., Schneider, D. P., Vargas-magana, M., & Willmer, C. N. (2013). An optimized correlation function estimator for galaxy surveys. Astronomy and Astrophysics, 554(Issue), A131. doi:10.1051/0004-6361/201220790
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  Measuring the two-point correlation function of the galaxies in the Universe gives access to the underlying dark matter distribution, which is related to cosmological parameters and to the physics of the primordial Universe. The estimation of the correlation function for current galaxy surveys makes use of the Landy-Szalay estimator, which is supposed to reach minimal variance. This is only true, however, for a vanishing correlation function. We study the Landy-Szalay estimator when these conditions are not fulfilled and propose a new estimator that provides the smallest variance for a given survey geometry. Our estimator is a linear combination of ratios between pair counts of data and/or random catalogues (DD, RR, and DR). The optimal combination for a given geometry is determined by using lognormal mock catalogues. The resulting estimator is biased in a model-dependent way, but we propose a simple iterative procedure for obtaining an unbiased model-independent estimator. Our method can be easily applied to any dataset and requires few extra mock catalogues compared to the standard Landy-Szalay analysis. Using various sets of simulated data (lognormal, second-order LPT, and N-body), we obtain a 20–25% gain on the error bars on the two-point correlation function for the SDSS geometry and ΛCDM correlation function. When applied to SDSS data (DR7 and DR9), we achieve a similar gain on the correlation functions, which translates into a 10–15% improvement over the estimation of the densities of matter Ωm and dark energy ΩΛ in an open ΛCDM model. The constraints derived from DR7 data with our estimator are similar to those obtained with the DR9 data and the Landy-Szalay estimator, which covers a volume twice as large and has a density that is three times higher.
• Bielby, R. M., Brimioulle, F., Cappelluti, N., Coil, A. L., Connelly, J. L., Cooper, M. C., Davis, M., Erfanianfar, G., Faber, S. M., Finoguenov, A., Gerke, B. F., Gwyn, S., Jeltema, T. E., Kocevski, D. D., Laird, E. S., Lerchster, M., Mccracken, H. J., Mirkazemi, M., Nandra, K., , Newman, J. A., et al. (2013). X-ray groups of galaxies in the AEGIS deep and wide fields. The Astrophysical Journal, 765(2), 117. doi:10.1088/0004-637x/765/2/117
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  We present the results of a search for extended X-ray sources and their corresponding galaxy groups from 800 ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). This yields one of the largest X-ray-selected galaxy group catalogs from a blind survey to date. The red-sequence technique and spectroscopic redshifts allow us to identify 100% of reliable sources, leading to a catalog of 52 galaxy groups. These groups span the redshift range z ~ 0.066-1.544 and virial mass range M 200 ~ 1.34 × 1013-1.33 × 1014 M ☉. For the 49 extended sources that lie within DEEP2 and DEEP3 Galaxy Redshift Survey coverage, we identify spectroscopic counterparts and determine velocity dispersions. We select member galaxies by applying different cuts along the line of sight or in projected spatial coordinates. A constant cut along the line of sight can cause a large scatter in scaling relations in low-mass or high-mass systems depending on the size of the cut. A velocity-dispersion-based virial radius can cause a larger overestimation of velocity dispersion in comparison to an X-ray-based virial radius for low-mass systems. There is no significant difference between these two radial cuts for more massive systems. Independent of radial cut, an overestimation of velocity dispersion can be created in the case of the existence of significant substructure and compactness in X-ray emission, which mostly occur in low-mass systems. We also present a comparison between X-ray galaxy groups and optical galaxy groups detected using the Voronoi-Delaunay method for DEEP2 data in this field.
• Bundy, K., Cooper, M. C., Davis, M., Dekel, A., Dutton, A. A., Faber, S. M., Faber, S. M., Gerke, B. F., Koo, D. C., Newman, J. A., Noeske, K. G., Salim, S., Weiner, B. J., Willmer, C. N., Woo, J., & Yan, R. (2013). Dependence of galaxy quenching on halo mass and distance from its centre. Monthly Notices of the Royal Astronomical Society, 428(4), 3306-3326. doi:10.1093/mnras/sts274
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  We study the dependence of star-formation quenching on galaxy mass and environment, in the SDSS (z~0.1) and the AEGIS (z~1). It is crucial that we define quenching by low star-formation rate rather than by red colour, given that one third of the red galaxies are star forming. We address stellar mass M*, halo mass Mh, density over the nearest N neighbours deltaN, and distance to the halo centre D. The fraction of quenched galaxies appears more strongly correlated with Mh at fixed M* than with M* at fixed Mh, while for satellites quenching also depends on D. We present the M*-Mh relation for centrals at z~1. At z~1, the dependence of quenching on M* at fixed Mh is somewhat more pronounced than at z~0, but the quenched fraction is low (10%) and the haloes are less massive. For satellites, M*-dependent quenching is noticeable at high D, suggesting a quenching dependence on sub-halo mass for recently captured satellites. At small D, where satellites likely fell in more than a few Gyr ago, quenching strongly depends on Mh, and not on M*. The Mh-dependence of quenching is consistent with theoretical wisdom where virial shock heating in massive haloes shuts down accretion and triggers ram-pressure stripping, causing quenching. The interpretation of deltaN is complicated by the fact that it depends on the number of observed group members compared to N, motivating the use of D as a better measure of local environment.
• Coil, A. L., Connolly, A. J., Conroy, C., Cooper, M. C., Davis, M., Dutton, A. A., Faber, S. M., Finkbeiner, D. P., Gerke, B. F., Guhathakurta, P., Harker, J. J., Kaiser, N., Kassin, S. A., Kirby, E. N., Konidaris, N. P., Koo, D. C., Lai, K., Lemaux, B. C., Lin, L., , Lotz, J. M., et al. (2013). The DEEP2 Galaxy Redshift Survey: Design, Observations, Data Reduction, and Redshifts. Astrophysical Journal Supplement Series, 208(1), 1-57. doi:10.1088/0067-0049/208/1/5
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  We describe the design and data analysis of the DEEP2 Galaxy Redshift Survey, the densest and largest high-precision redshift survey of galaxies at z ~ 1 completed to date. The survey was designed to conduct a comprehensive census of massive galaxies, their properties, environments, and large-scale structure down to absolute magnitude M_B = −20 at z ~ 1 via ~90 nights of observation on the Keck telescope. The survey covers an area of 2.8 deg^2 divided into four separate fields observed to a limiting apparent magnitude of R_(AB) = 24.1. Objects with z ≾0.7 are readily identifiable using BRI photometry and rejected in three of the four DEEP2 fields, allowing galaxies with z > 0.7 to be targeted ~2.5 times more efficiently than in a purely magnitude-limited sample. Approximately 60% of eligible targets are chosen for spectroscopy, yielding nearly 53,000 spectra and more than 38,000 reliable redshift measurements. Most of the targets that fail to yield secure redshifts are blue objects that lie beyond z ~ 1.45, where the [O ii] 3727 A doublet lies in the infrared. The DEIMOS 1200 line mm^(−1) grating used for the survey delivers high spectral resolution (R ~ 6000), accurate and secure redshifts, and unique internal kinematic information. Extensive ancillary data are available in the DEEP2 fields, particularly in the Extended Groth Strip, which has evolved into one of the richest multiwavelength regions on the sky. This paper is intended as a handbook for users of the DEEP2 Data Release 4, which includes all DEEP2 spectra and redshifts, as well as for the DEEP2 DEIMOS data reduction pipelines. Extensive details are provided on object selection, mask design, biases in target selection and redshift measurements, the spec2d two-dimensional data-reduction pipeline, the spec1d automated redshift pipeline, and the zspec visual redshift verification process, along with examples of instrumental signatures or other artifacts that in some cases remain after data reduction. Redshift errors and catastrophic failure rates are assessed through more than 2000 objects with duplicate observations. Sky subtraction is essentially photon-limited even under bright OH sky lines; we describe the strategies that permitted this, based on high image stability, accurate wavelength solutions, and powerful B-spline modeling methods. We also investigate the impact of targets that appear to be single objects in ground-based targeting imaging but prove to be composite in Hubble Space Telescope data; they constitute several percent of targets at z ~ 1, approaching ~5%–10% at z > 1.5. Summary data are given that demonstrate the superiority of DEEP2 over other deep high-precision redshift surveys at z ~ 1 in terms of redshift accuracy, sample number density, and amount of spectral information. We also provide an overview of the scientific highlights of the DEEP2 survey thus far.
• Im, M., Jeon, Y., Karouzos, M., Kim, S. J., Ko, J., Lee, H. M., Papovich, C., Shim, H., Weiner, B. J., & Willmer, C. N. (2013). HECTOSPEC AND HYDRA SPECTRA OF INFRARED LUMINOUS SOURCES IN THE AKARI NORTH ECLIPTIC POLE SURVEY FIELD. Astrophysical Journal Supplement Series, 207(2), 37. doi:10.1088/0067-0049/207/2/37
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  We present spectra of 1796 sources selected in the AKARI North Ecliptic Pole Wide Survey field, obtained with MMT/Hectospec and WIYN/Hydra, for which we measure 1645 redshifts. We complemented the generic flux-limited spectroscopic surveys at 11 {mu}m and 15 {mu}m, with additional sources selected based on the MIR and optical colors. In MMT/Hectospec observations, the redshift identification rates are {approx}80% for objects with R < 21.5 mag. On the other hand, in WIYN/Hydra observations, the redshift identification rates are {approx}80% at R magnitudes brighter than 19 mag. The observed spectra were classified through the visual inspection or from the line diagnostics. We identified 1128 star-forming or absorption-line-dominated galaxies, 198 Type-1 active galactic nuclei (AGNs), 8 Type-2 AGNs, 121 Galactic stars, and 190 spectra in unknown category due to low signal-to-noise ratio. The spectra were flux-calibrated but to an accuracy of 0.1-0.18 dex for most of the targets and worse for the remainder. We derive star formation rates (SFRs) from the mid-infrared fluxes or from the optical emission lines, showing that our sample spans an SFR range of 0.1 to a few hundred M{sub Sun} yr{sup -1}. We find that the extinction inferred from the difference between the IR and opticalmore » SFR increases as the IR luminosity increases but with a large scatter.« less
• Lotz, J. M., Papovich, C., Faber, S. M., Ferguson, H. C., Guo, Y., Koekemoer, A. M., Lee, K., Momcheva, I., Rudnick, G., Saintonge, A., Grogin, N. A., Kocevski, D. D., Mcintosh, D. H., Tran, K. H., Wel, A. V., & Willmer, C. N. (2013). CAUGHT IN THE ACT: THE ASSEMBLY OF MASSIVE CLUSTER GALAXIES AT z = 1.62. The Astrophysical Journal, 773(2), 154. doi:10.1088/0004-637x/773/2/154
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  We present the recent merger history of massive galaxies in a spectroscopically confirmed proto-cluster at z = 1.62. Using Hubble Space Telescope WFC3 near-infrared imaging from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, we select cluster and z ~ 1.6 field galaxies with M star ≥ 3 × 1010 M ☉, to determine the frequency of double nuclei or close companions within projected separations less than 20 kpc co-moving. We find that four out of five spectroscopically confirmed massive proto-cluster galaxies have double nuclei, and 57 % of all M star ≥ 3 × 1010 M ☉ cluster candidates are observed in either close pair systems or have double nuclei. In contrast, only 11% ± 3% of the field galaxies are observed in close pair/double nuclei systems. After correcting for the contribution from random projections, the implied merger rate per massive galaxy in the proto-cluster is ~3-10 times higher than the merger rate of massive field galaxies at z ~ 1.6. Close pairs in the cluster have minor merger stellar mass ratios (M primary: M satellite ≥ 4), while the field pairs consist of both major and minor mergers. At least half of the cluster mergers are gas-poor, as indicated by their red colors and low 24 μm fluxes. Two of the double-nucleated cluster members have X-ray detected active galactic nuclei with Lx > 1043 erg s–1, and are strong candidates for dual or offset super-massive black holes. We conclude that the massive z = 1.62 proto-cluster galaxies are undergoing accelerated assembly via minor mergers, and discuss the implications for galaxy evolution in proto-cluster environments.
• Palanque-Delabrouille, N., Magneville, C., Eftekharzadeh, S., Myers, A., Petitjean, P., Aubourg, E., McGreer, I., Fan, X., Dey, A., Schlegel, D., Bailey, S., Bizayev, D., Bolton, A., Dawson, K., Ebelke, G., Ge, J., Malanushenko, E., Malanushenko, V., Oravetz, D., , Pan, K., et al. (2013). Luminosity function from dedicated SDSS-III and MMT data of quasars in 0.7 < z < 4.0 selected with a new approach. Astronomy and Astrophysics, 551. doi:10.1051/0004-6361/201220379
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  We present a measurement of the quasar luminosity function in the range 0.68 < z < 4 down to extinction corrected magnitude gdered = 22.5, using a simple and well understood target selection technique based on the time-variability of quasars. The completeness of our sample was derived directly from a control sample of quasars, without requiring complex simulations of quasar light-curves or colors. A total of 1877 quasar spectra were obtained from dedicated programs on the Sloan telescope (as part of the SDSS-III/BOSS survey) and on the Multiple Mirror Telescope. They allowed us to derive the quasar luminosity function. It agrees well with results previously published in the redshift range 0.68 < z < 2.6. Our deeper data allow us to extend the measurement to z = 4. We measured quasar densities to gdered < 22.5, obtaining 30 QSO per deg2 at z < 1, 99 QSO per deg 2 for 1 < z < 2.15, and 47 QSO per deg2 at z > 2.15. Using pure luminosity evolution models, we fitted our LF measurements and predicted quasar number counts as a function of redshift and observed magnitude. These predictions are useful inputs for future cosmology surveys such as those relying on the observation of quasars to measure baryon acoustic oscillations. © 2013 ESO.
• Willmer, C. N., Weiner, B., Ashby, M. L., Barmby, P., Coil, A. L., Faber, S. M., Fazio, G. G., Huang, J. S., Koo, D. C., Luo, Z., Magdis, G. E., Newman, J. A., Rigopoulou, D., Shu, C., Wang, T., Weiner, B. J., Willner, S. P., & Zheng, X. Z. (2013). MULTI-WAVELENGTH STUDY OF A COMPLETE IRAC 3.6 μm SELECTED GALAXY SAMPLE: A FAIR CENSUS OF RED AND BLUE POPULATIONS AT REDSHIFTS 0.4-1.2. The Astrophysical Journal, 766(1), 21. doi:10.1088/0004-637x/766/1/21
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  We present a multi-wavelength study of a 3.6 mu m selected galaxy sample in the Extended Groth Strip (EGS). The sample is complete for galaxies with stellar mass >10(9.5) M-circle dot and redshift 0.4 3 sigma errors) is about 3.5%. A new method of validation based on pair statistics confirms the estimate of standard deviation even for galaxies lacking spectroscopic redshifts. Basic galaxy properties measured include rest-frame U - B colors, B- and K-band absolute magnitudes, and stellar masses. We divide the sample into quiescent and star-forming galaxies according to their rest-frame U - B colors and 24-3.6 mu m flux density ratios and derive rest K-band luminosity functions and stellar mass functions for quiescent, star-forming, and all galaxies. The results show that massive, quiescent galaxies were in place by z approximate to 1, but lower mass galaxies generally ceased their star formation at later epochs.
• Barden, M., Capak, P. L., Comerford, J. M., Conselice, C. J., Cooper, M. C., Davis, M., Faber, S. M., Griffith, R. L., Kirkpatrick, J. D., Koekemoer, A. M., Koo, D. C., Lotz, J. M., Moustakas, L. A., Newman, J. A., Noeske, K. G., Scoville, N., Sheth, K., Shopbell, P. L., Stern, D., , Weiner, B. J., et al. (2012). The Advanced Camera for Surveys General Catalog: Structural Parameters for Approximately Half a Million Galaxies. Astrophysical Journal Supplement Series, 200(1), 9. doi:10.1088/0067-0049/200/1/9
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  We present the Advanced Camera for Surveys General Catalog (ACS-GC), a photometric and morphological database using publicly available data obtained with the Advanced Camera for Surveys (ACS) instrument on the Hubble Space Telescope. The goal of the ACS-GC database is to provide a large statistical sample of galaxies with reliable structural and distance measurements to probe the evolution of galaxies over a wide range of look-back times. The ACS-GC includes approximately 470,000 astronomical sources (stars + galaxies) derived from the AEGIS, COSMOS, GEMS, and GOODS surveys. GALAPAGOS was used to construct photometric (SEXTRACTOR) and morphological (GALFIT) catalogs. The analysis assumes a single Sersic model for each object to derive quantitative structural parameters. We include publicly available redshifts from the DEEP2, COMBO-17, TKRS, PEARS, ACES, CFHTLS, and zCOSMOS surveys to supply redshifts (spectroscopic and photometric) for a considerable fraction (~74%) of the imaging sample. The ACS-GC includes color postage stamps, GALFIT residual images, and photometry, structural parameters, and redshifts combined into a single catalog.
• Barro, G., Bell, E. F., Bundy, K., Cheung, E., Coil, A. L., Conselice, C. J., Cooper, M. C., Davis, M., Dekel, A., Dominguez, A., Dutton, A. A., Faber, S. M., Fang, J. J., Huang, J. S., Kassin, S. A., Kocevski, D. D., Koekemoer, A. M., Koo, D. C., Lin, L., , Lotz, J. M., et al. (2012). The dependence of quenching upon the inner structure of galaxies at 0.5 ≤ $z$ < 0.8 in the DEEP2/AEGIS survey. The Astrophysical Journal, 760(2), 131. doi:10.1088/0004-637x/760/2/131
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  The shutdown of star formation in galaxies is generally termed 'quenching'. Quenching may occur through a variety of processes, e.g., active galactic nucleus (AGN) feedback, stellar feedback, or the shock heating of gas in the dark matter halo. However, which mechanism(s) is, in fact, responsible for quenching is still in question. This paper addresses quenching by searching for traces of possible quenching processes through their effects on galaxy structural parameters such as stellar mass (M {sub *}), M {sub *}/r {sub e}, surface stellar mass density ({approx}M {sub *}/r {sup 2} {sub e}), and Sersic index (n). We analyze the rest-frame U - B color correlations versus these structural parameters using a sample of galaxies in the redshift range 0.5 { 2.3 galaxies. We hypothesize that their Sersic values may be distorted by bursts of star formation, AGNs, and/or poor fits, leading us to consider central surface stellar mass density, {Sigma}*{sub 1kpc}, as an alternative to Sersic index. Not only does {Sigma}*{sub 1kpc} correct the outliers, but it also forms a tight relationship with color, suggesting that the innermost structure of galaxies is most physically linked with quenching. Furthermore, at z {approx} 0.65, the majority of the blue cloud galaxies cannot simply fade onto the red sequence since their GIM2D bulge masses are only half as large on average as the bulge masses of similar red sequence galaxies, thus demonstrating that stellar mass must absolutely increase at the centers of galaxies as they quench. We discuss a two-stage model for quenching in which galaxy star formation rates are controlled by their dark halos while they are still in the blue cloud and a second quenching process sets in later, associated with the central stellar mass buildup. The mass buildup is naturally explained by any non-axisymmetric features in the potential, such as those induced by mergers and/or disk instabilities. However, the identity of the second quenching agent is still unknown. We have placed our data catalog online.« less
• Bassett, R., Bell, E. F., Conselice, C. J., Dekel, A., Dunlop, J. S., Faber, S. M., Farrah, D., Ferguson, H. C., Finkelstein, S. L., Finkelstein, K. D., Guo, Y., Haussler, B., Kocevski, D. D., Koekemoer, A. M., Koo, D. C., Lotz, J. M., Mcgrath, E. J., Mcintosh, D. H., Mclure, R. J., , Momcheva, I., et al. (2012). CANDELS observations of the structural properties of cluster galaxies at z = 1.62. The Astrophysical Journal, 750(2), 93. doi:10.1088/0004-637x/750/2/93
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  We discuss the structural and morphological properties of galaxies in a z = 1.62 proto-cluster using near-IR imaging data from Hubble Space Telescope Wide Field Camera 3 data of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). The cluster galaxies exhibit a clear color-morphology relation: galaxies with colors of quiescent stellar populations generally have morphologies consistent with spheroids, and galaxies with colors consistent with ongoing star formation have disk-like and irregular morphologies. The size distribution of the quiescent cluster galaxies shows a deficit of compact ({approx}< 1 kpc), massive galaxies compared to CANDELS field galaxies at z = 1.6. As a result, the cluster quiescent galaxies have larger average effective sizes compared to field galaxies at fixed mass at greater than 90% significance. Combined with data from the literature, the size evolution of quiescent cluster galaxies is relatively slow from z {approx_equal} 1.6 to the present, growing as (1 + z){sup -0.6{+-}0.1}. If this result is generalizable, then it implies that physical processes associated with the denser cluster region seem to have caused accelerated size growth in quiescent galaxies prior to z = 1.6 and slower subsequent growth at z < 1.6 compared to galaxies in the lower densitymore » field. The quiescent cluster galaxies at z = 1.6 have higher ellipticities compared to lower redshift samples at fixed mass, and their surface-brightness profiles suggest that they contain extended stellar disks. We argue that the cluster galaxies require dissipationless (i.e., gas-poor or 'dry') mergers to reorganize the disk material and to match the relations for ellipticity, stellar mass, size, and color of early-type galaxies in z < 1 clusters.« less
• Bergeron, J., Bock, J., Cooray, A., Dai, Y. S., Elvis, M., Fazio, G. G., Hatziminaoglou, E., Huang, J., Ibar, E., Magdis, G. E., Oliver, S. J., Omont, A., Page, M. J., Perez-fournon, I., Rigopoulou, D., Roseboom, I. G., Scott, D., Symeonidis, M., Trichas, M., , Vieira, J. D., et al. (2012). A Population of Dust-rich Quasars at z ~ 1.5. The Astrophysical Journal, 753(1), 33. doi:10.1088/0004-637x/753/1/33
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  We report Herschel SPIRE (250, 350, and 500 μm) detections of 32 quasars with redshifts 0.5 ≤z < 3.6 from the Herschel Multi-tiered Extragalactic Survey (HerMES). These sources are from a MIPS 24 μm flux-limited sample of 326 quasars in the Lockman Hole Field. The extensive multi-wavelength data available in the field permit construction of the rest-frame spectral energy distributions (SEDs) from ultraviolet to the mid-infrared for all sources, and to the far-infrared (FIR) for the 32 objects. Most quasars with Herschel FIR detections show dust temperatures in the range of 25-60 K, with a mean of 34 K. The FIR luminosities range from 10^(11.3) to 10^(13.5) L_☉, qualifying most of their hosts as ultra- or hyper-luminous infrared galaxies. These FIR-detected quasars may represent a dust-rich population, but with lower redshifts and fainter luminosities than quasars observed at ~1 mm. However, their FIR properties cannot be predicted from shorter wavelengths (0.3-20 μm, rest frame), and the bolometric luminosities derived using the 5100 A index may be underestimated for these FIR-detected quasars. Regardless of redshift, we observed a decline in the relative strength of FIR luminosities for quasars with higher near-infrared luminosities.
• Chen, Y., Coil, A. L., Davis, M., Guo, Q., Jing, Y. P., Kauffmann, G., Li, C., Lucia, G. D., White, S. D., Willmer, C. N., & Zhang, W. (2012). Autocorrelations of stellar light and mass at z∼ 0 and ∼1: from SDSS to DEEP2. Monthly Notices of the Royal Astronomical Society, 419(2), 1557-1565. doi:10.1111/j.1365-2966.2011.19817.x
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  We present measurements of projected autocorrelation functions wp(rp) for the stellar mass of galaxies and for their light in the U, B and V bands, using data from the third data release of the DEEP2 Galaxy Redshift Survey and the final data release of the Sloan Digital Sky Survey (SDSS). We investigate the clustering bias of stellar mass and light by comparing these to projected autocorrelations of dark matter estimated from the Millennium Simulations (MS) at z = 1 and 0.07, the median redshifts of our galaxy samples. All of the autocorrelation and bias functions show systematic trends with spatial scale and waveband which are impressively similar at the two redshifts. This shows that the well-established environmental dependence of stellar populations in the local Universe is already in place at z = 1. The recent MS-based galaxy formation simulation of Guo et al. (2011) reproduces the scale-dependent clustering of luminosity to an accuracy better than 30% in all bands and at both redshifts, but substantially overpredicts mass autocorrelations at separations below about 2 Mpc. Further comparison of the shapes of our stellar mass bias functions with those predicted by the model suggests that both the SDSS and DEEP2 data prefer a fluctuation amplitude of σ8 � 0.8 rather than the σ8 = 0.9 assumed by the MS.
• Clerc, N., Maughan, B. J., Pacaud, F., Papovich, C., Pierre, M., & Willmer, C. N. (2012). A Chandra view of the z=1.62 galaxy cluster IRC-0218A. Astronomy and Astrophysics, 540(Issue), A4. doi:10.1051/0004-6361/201118169
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  Context. Very few z > 1.5 clusters of galaxies are currently known. It is important to study the properties of galaxies in these clusters and the intra-cluster medium and, furthermore, to cross-check the reliability of the various mass estimates. This will help to clarify the process of structure formation and how distant clusters may be used to constrain cosmology. Aims. We present a 84 ks Chandra observation of IRC-0218A, a cluster of galaxies inferred by the presence of a galaxy overdensity in the infrared at a redshift of 1.62 and associated with some XMM emission. Methods. We performed a spatial analysis of the Chandra X-ray photon distribution. Results. The Chandra observation of IRC-0218A appears to be entirely dominated by a point source located at the centroid of the mid-infrared galaxy density. In addition, we detected weak extended emission (2.3σ) out to a radius of 25′′ with a flux of ∼3 × 10−15 erg s−1 cm−2 in the [0.3–2] keV band. Assuming that clusters evolve similarly, we infer a virial mass of M200 = 7.7(±3.8) × 1013 M . This is marginally compatible with our current estimate of the cluster dynamical mass (based on 10 redshifts), although there is no evidence that the galaxy peculiar velocities correspond to the motions of a virialized structure. The stellar mass enclosed in the inferred X-ray virial radius is estimated to be 1–2 × 1012 M . We provide a detailed account of 28 X-ray point sources detected in the field.
• Coil, A. L., Cooper, M. C., Davis, M., Dutton, A. A., Faber, S. M., Gerke, B. F., Guhathakurta, P., Konidaris, N. P., Koo, D. C., Lin, L., Newman, J. A., Noeske, K. G., Phillips, A. C., Rosario, D. J., Weiner, B. J., Willmer, C. N., & Yan, R. (2012). THE DEEP2 GALAXY REDSHIFT SURVEY: THE VORONOI-DELAUNAY METHOD CATALOG OF GALAXY GROUPS. The Astrophysical Journal, 751(1), 50. doi:10.1088/0004-637x/751/1/50
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  We present a public catalog of galaxy groups constructed from the spectroscopic sample of galaxies in the fourth data release from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Galaxy Redshift Survey, including the Extended Groth Strip (EGS). The catalog contains 1165 groups with two or more members in the EGS over the redshift range 0 0.6 in the rest of DEEP2. Twenty-five percent of EGS galaxies and fourteen percent of high-z DEEP2 galaxies are assigned to galaxy groups. The groups were detected using the Voronoi-Delaunay method (VDM) after it has been optimized on mock DEEP2 catalogs following similar methods to those employed in Gerke et al. In the optimization effort, we have taken particular care to ensure that the mock catalogs resemble the data as closely as possible, and we have fine-tuned our methods separately on mocks constructed for the EGS and the rest of DEEP2. We have also probed the effect of the assumed cosmology on our inferred group-finding efficiency by performing our optimization on three different mock catalogs with different background cosmologies, finding large differences in the group-finding success we can achieve for these different mocks. Using the mock catalog whose background cosmology is most consistent with current data, we estimate that the DEEP2 group catalog is 72% complete and 61% pure (74% and 67% for the EGS) and that the group finder correctly classifies 70% of galaxies that truly belong to groups, with an additional 46% of interloper galaxies contaminating the catalog (66% and 43% for the EGS). We also confirm that the VDM catalog reconstructs the abundance of galaxy groups with velocity dispersions above ~300 km s^(–1) to an accuracy better than the sample variance, and this successful reconstruction is not strongly dependent on cosmology. This makes the DEEP2 group catalog a promising probe of the growth of cosmic structure that can potentially be used for cosmological tests.
• Coil, A. L., Cooper, M. C., Davis, M., Dutton, A. A., Faber, S. M., Griffith, R. L., Guhathakurta, P., Koo, D. C., Lotz, J. M., Newman, J. A., Weiner, B. J., Willmer, C. N., & Yan, R. (2012). The DEEP3 Galaxy Redshift Survey: the impact of environment on the size evolution of massive early-type galaxies at intermediate redshift. Monthly Notices of the Royal Astronomical Society, 419(4), 3018-3027. doi:10.1111/j.1365-2966.2011.19938.x
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  Using data drawn from the DEEP2 and DEEP3 Galaxy Redshift Surveys, we investigate the relationship between the environment and the structure of galaxies residing on the red sequence at intermediate redshift. Within the massive (10 < log_(10)(M_(★)/h^(−2) M_⊙) < 11) early-type population at 0.4 < z < 1.2, we find a significant correlation between local galaxy overdensity (or environment) and galaxy size, such that early-type systems in higher density regions tend to have larger effective radii (by ∼0.5 h^(−1) kpc or 25 per cent larger) than their counterparts of equal stellar mass and Sersic index in lower density environments. This observed size–density relation is consistent with a model of galaxy formation in which the evolution of early-type systems at z < 2 is accelerated in high-density environments such as groups and clusters and in which dry, minor mergers (versus mechanisms such as quasar feedback) play a central role in the structural evolution of the massive, early-type galaxy population.
• Coil, A. L., Cooper, M. C., Devriendt, J., Dutton, A. A., Faber, S. M., Gardner, J. P., Guhathakurta, P., Kassin, S. A., Koo, D. C., Metevier, A. J., Metevier, A. J., Noeske, K. G., Primack, J. R., Weiner, B. J., & Willmer, C. N. (2012). The Epoch of Disk Settling: z ~ 1 to Now. The Astrophysical Journal, 758(2), 106. doi:10.1088/0004-637x/758/2/106
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  We present evidence from a sample of 544 galaxies from the DEEP2 Survey for evolution of the internal kinematics of blue galaxies with stellar masses ranging 8.0 < log M {sub *}(M {sub Sun }) < 10.7 over 0.2 < z < 1.2. DEEP2 provides galaxy spectra and Hubble imaging from which we measure emission-line kinematics and galaxy inclinations, respectively. Our large sample allows us to overcome scatter intrinsic to galaxy properties in order to examine trends in kinematics. We find that at a fixed stellar mass, galaxies systematically decrease in disordered motions and increase in rotation velocity and potential well depth with time. Massive galaxies are the most well ordered at all times examined, with higher rotation velocities and less disordered motions than less massive galaxies. We quantify disordered motions with an integrated gas velocity dispersion corrected for beam smearing ({sigma} {sub g}). It is unlike the typical pressure-supported velocity dispersion measured for early type galaxies and galaxy bulges. Because both seeing and the width of our spectral slits comprise a significant fraction of the galaxy sizes, {sigma} {sub g} integrates over velocity gradients on large scales which can correspond to non-ordered gas kinematics. We compile measurements of galaxymore » kinematics from the literature over 1.2 < z < 3.8 and do not find any trends with redshift, likely for the most part, because these data sets are biased toward the most highly star-forming systems. In summary, over the last {approx}8 billion years since z = 1.2, blue galaxies evolve from disordered to ordered systems as they settle to become the rotation-dominated disk galaxies observed in the universe today, with the most massive galaxies being the most evolved at any time.« less
• Cooper, M. C., Dickinson, M., Juneau, S., Lotz, J. M., Newman, J. A., Papovich, C., Salim, S., Walth, G., Weiner, B. J., Willmer, C. N., & Yan, R. (2012). The Arizona CDFS Environment Survey (ACES): A Magellan/IMACS Spectroscopic Survey of the Chandra Deep Field-South†. Monthly Notices of the Royal Astronomical Society, 425(3), 2116-2127. doi:10.1111/j.1365-2966.2012.21524.x
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  *This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.
• Fujishiro, N., Goto, T., Hanami, H., Im, M., Ishigaki, T., Krumpe, M., Lee, M. G., Lee, H. M., Matsuhara, H., Miyaji, T., Nakanishi, K., Ohyama, Y., Oyabu, S., Serjeant, S., Shim, H., Takagi, T., Umetsu, K., Wada, T., White, G. J., & Willmer, C. N. (2012). Star Formation and AGN Activity in Galaxies Classified Using the 1.6 μm Bump and PAH Features at z = 0.4-2. Publications of the Astronomical Society of Japan, 64(4), 70. doi:10.1093/pasj/64.4.70
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  We studied the star-formation and AGN activity of massive galaxies in the redshift range z = 0.4-2, which were detected in a deep survey field using the AKARI InfraRed (IR) astronomical satellite and Subaru telescope toward the North Ecliptic Pole (NEP). The AKARI/IRC Mid-InfraRed (MIR) multiband photometry was used to trace the star-forming activities with Polycyclic Aromatic Hydrocarbon (PAH) emission, which is effective not only to distinguish between star-forming and AGN galaxies, but also to estimate the Star Formation Rate (SFR) with converting its flux to the total emitting IR (TIR) luminosity. In combination with the analyses of the stellar components, we studied the MIR SED features of star-forming and AGN-harboring galaxies, which we summarize below: (1) The rest-frame 7.7-μm and 5-μm luminosities are good tracers of star-forming and AGN activities from their PAH and dusty tori emissions, respectively. (2) For dusty star-forming galaxies without AGN, their SFR shows a correlation that is nearly proportional to their stellar mass, and their specific SFR (sSFR) per unit stellar mass increases with redshift. Extinctions estimated from their TIR luminosities are larger than those from their optical SED fittings, which may be caused by geometric variations of dust in them. (3) Even for dusty star-forming galaxies with AGN, SFRs can be derived from their TIR luminosities with subtraction of the obscured AGN contribution, which indicates that their SFRs were possibly quenched around z ≃ 0.8 compared with those without AGN. (4) The AGN activity from their rest-frame 5-μm luminosity suggests that their Super Massive Black Holes (SMBHs) could already have grown to ≃ 3 × 10 8 M ⊙ in most massive galaxies with 10 11 M ⊙ at z > 1.2, and the mass relation between SMBHs and their host galaxies has already become established by z ≃ 1-2.
• Hwang, H. S., Im, M., Jeon, Y., Kim, S. J., Ko, J., Lee, M. G., Lee, H. M., Malkan, M. A., Matsuhara, H., Oyabu, S., Papovich, C., Shim, H., Takagi, T., Weiner, B. J., & Willmer, C. N. (2012). AKARI OBSERVATION OF THE NORTH ECLIPTIC POLE (NEP) SUPERCLUSTER AT z = 0.087: MID-INFRARED VIEW OF TRANSITION GALAXIES. The Astrophysical Journal, 745(2), 181-181. doi:10.1088/0004-637x/745/2/181
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  We present the mid-infrared (MIR) properties of galaxies within a supercluster in the north ecliptic pole region at z ~ 0.087 observed with the AKARI satellite. We use data from the AKARI NEP-Wide (5.4 deg^2) IR survey and the CLusters of galaxies EVoLution studies (CLEVL) mission program. We show that near-IR (3 μm)-mid-IR (11 μm) color can be used as an indicator of the specific star formation rate and the presence of intermediate-age stellar populations. From the MIR observations, we find that red-sequence galaxies consist not only of passively evolving red early-type galaxies, but also of (1) "weak-SFGs" (disk-dominated star-forming galaxies that have star formation rates lower by ~4 × than blue-cloud galaxies) and (2) "intermediate-MXGs" (bulge-dominated galaxies showing stronger MIR dust emission than normal red early-type galaxies). These two populations can be a set of transition galaxies from blue, star-forming, late-type galaxies evolving into red, quiescent, early-type ones. We find that the weak-SFGs are predominant at intermediate masses (10^(10) M_☉ 10^(10.5) M_☉) at any galaxy density. The fraction of the intermediate-MXG among red-sequence galaxies at 10^(10) M_☉ < M_* < 10^(11) M_☉ also decreases as the density and mass increase. In particular, ~42% of the red-sequence galaxies with early-type morphologies are classified as intermediate-MXGs at intermediate densities. These results suggest that the star formation activity is strongly dependent on the stellar mass, but that the morphological transformation is mainly controlled by the environment.
• Ko, J., Im, M., Lee, H., Lee, M., Kim, S., Shim, H., Jeon, Y., Hwang, H., Willmer, C., Malkan, M., Papovich, C., Weiner, B., Matsuhara, H., Oyabu, S., & Takagi, T. (2012). AKARI observation of the north ecliptic pole (NEP) supercluster at z = 0.087: Mid-infrared view of transition galaxies. Astrophysical Journal, 745(2). doi:10.1088/0004-637X/745/2/181
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  We present the mid-infrared (MIR) properties of galaxies within a supercluster in the north ecliptic pole region at z ∼ 0.087 observed with the AKARI satellite. We use data from the AKARI NEP-Wide (5.4deg2) IR survey and the CLusters of galaxies EVoLution studies (CLEVL) mission program. We show that near-IR (3 μm)-mid-IR (11 μm) color can be used as an indicator of the specific star formation rate and the presence of intermediate-age stellar populations. From the MIR observations, we find that red-sequence galaxies consist not only of passively evolving red early-type galaxies, but also of (1) "weak-SFGs" (disk-dominated star-forming galaxies that have star formation rates lower by ∼4 × than blue-cloud galaxies) and (2) "intermediate-MXGs" (bulge-dominated galaxies showing stronger MIR dust emission than normal red early-type galaxies). These two populations can be a set of transition galaxies from blue, star-forming, late-type galaxies evolving into red, quiescent, early-type ones. We find that the weak-SFGs are predominant at intermediate masses (1010 M ⊙ < M * < 1010.5 M ⊙) and are typically found in local densities similar to the outskirts of galaxy clusters. As much as 40% of the supercluster member galaxies in this mass range can be classified as weak-SFGs, but their proportion decreases to 10 10.5 M ⊙) at any galaxy density. The fraction of the intermediate-MXG among red-sequence galaxies at 1010 M ⊙ < M * < 1011 M ⊙ also decreases as the density and mass increase. In particular, ∼42% of the red-sequence galaxies with early-type morphologies are classified as intermediate-MXGs at intermediate densities. These results suggest that the star formation activity is strongly dependent on the stellar mass, but that the morphological transformation is mainly controlled by the environment. © 2012. The American Astronomical Society. All rights reserved.
• Momcheva, I., Papovich, C., Rudnick, G. H., Tran, K. H., & Willmer, C. N. (2012). A TALE OF DWARFS AND GIANTS: USING A z = 1.62 CLUSTER TO UNDERSTAND HOW THE RED SEQUENCE GREW OVER THE LAST 9.5 BILLION YEARS*. The Astrophysical Journal, 755(1), 14. doi:10.1088/0004-637x/755/1/14
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  We study the red sequence in a cluster of galaxies at z = 1.62 and follow its evolution over the intervening 9.5?Gyr to the present day. Using deep YJKs imaging with the HAWK-I instrument on the Very Large Telescope, we identify a tight red sequence and construct its rest-frame i-band luminosity function (LF). There is a marked deficit of faint red galaxies in the cluster that causes a turnover in the LF. We compare the red-sequence LF to that for clusters at z 0.6. In this model the cluster accretes blue galaxies from the field whose star formation is quenched and who are subsequently allowed to merge. We find that three to four mergers among cluster galaxies during the 4?Gyr between z = 1.62 and z = 0.6 match the observed LF evolution between the two redshifts. The inferred merger rate is consistent with other studies of this cluster. Our result supports the picture that galaxy merging during the major growth phase of massive clusters is an important process in shaping the red-sequence population at all luminosities.
• Willmer, C. N., Babu, S., Beletic, J. W., Blake, P., Cleveland, K., Cofie, E., Eegholm, B., Engelbracht, C. W., Greenhouse, M. A., Hall, D. N., Hill, R. J., Hoffman, A. W., Jeffers, B., Jhabvala, C. A., Kimble, R. A., Kohn, S. E., Kopp, R., Lee, D., Leidecker, H., , Lindler, D. J., et al. (2012). Commentary: JWST near-infrared detector degradation— finding the problem, fixing the problem, and moving forward. AIP Advances, 2(2), 021901. doi:10.1063/1.4733534
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  The James Webb Space Telescope (JWST) is the successor to the Hubble Space Telescope. JWST will be an infrared-optimized telescope, with an approximately 6.5 m diameter primary mirror, that is located at the Sun-Earth L2 Lagrange point. Three of JWST’s four science instruments use Teledyne HgCdTe HAWAII-2RG (H2RG) near infrared detector arrays. During 2010, the JWST Project noticed that a few of its 5 μm cutoff H2RG detectors were degrading during room temperature storage, and NASA chartered a “Detector Degradation Failure Review Board” (DD-FRB) to investigate. The DD-FRB determined that the root cause was a design flaw that allowed indium to interdiffuse with the gold contacts and migrate into the HgCdTe detector layer. Fortunately, Teledyne already had an improved design that eliminated this degradation mechanism. During early 2012, the improved H2RG design was qualified for flight and JWST began making additional H2RGs. In this article, we present the two public DD-FRB “Executive Summaries” that: (1) determined the root cause of the detector degradation and (2) defined tests to determine whether the existing detectors are qualified for flight. We supplement these with a brief introduction to H2RG detector arrays, some recent measurements showing that the performance of the improved design meets JWST requirements, and a discussion of how the JWST Project is using cryogenic storage to retard the degradation rate of the existing flight spare H2RGs.
• Aird, J. A., Coil, A. L., Cooper, M. C., Davis, M., Faber, S. M., Juneau, S., Lotz, J. M., Nandra, K., Newman, J. A., Willmer, C. N., & Yan, R. (2011). The DEEP3 Galaxy Redshift Survey: Keck/DEIMOS Spectroscopy in the GOODS-N Field. Astrophysical Journal Supplement Series, 193(1), 14. doi:10.1088/0067-0049/193/1/14
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  We present the results of spectroscopic observations in the GOODS-N field completed using DEIMOS on the Keck II telescope as part of the DEEP3 Galaxy Redshift Survey. Observations of 370 unique targets down to a limiting magnitude of R AB = 24.4 yielded 156 secure redshifts. In addition to redshift information, we provide sky-subtracted one- and two-dimensional spectra of each target. Observations were conducted following the procedures of the Team Keck Redshift Survey (TKRS), thereby producing spectra that augment the TKRS sample while maintaining the uniformity of its spectral database.
• Aird, J., Barmby, P., Bundy, K., Coil, A. L., Cooper, M. C., Davis, M., Faber, S. M., Fang, T., Georgakakis, A., Griffith, R. L., Ho, L. C., Koekemoer, A. M., Koo, D. C., Laird, E. S., Nandra, K., Newman, J. A., Park, S. Q., Sarajedini, V. L., Weiner, B. J., , Willmer, C. N., et al. (2011). AEGIS: DEMOGRAPHICS OF X-RAY AND OPTICALLY SELECTED ACTIVE GALACTIC NUCLEI. The Astrophysical Journal, 728(1), 38. doi:10.1088/0004-637x/728/1/38
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  We develop a new diagnostic method to classify galaxies into active galactic nucleus (AGN) hosts, star-forming galaxies, and absorption-dominated galaxies by combining the [O III]/Hβ ratio with rest-frame U – B color. This can be used to robustly select AGNs in galaxy samples at intermediate redshifts (z 1044 erg s-1 in our sample are not detected in our 200 ks Chandra images, most likely due to moderate or heavy absorption by gas near the AGN. The 2-7 keV detection rate of Seyfert 2s at z ~ 0.6 suggests that their column density distribution and Compton-thick fraction are similar to that of local Seyferts. Multiple sample selection techniques are needed to obtain as complete a sample as possible.
• Bundy, K., Clarke, F. J., Conselice, C. J., Cooper, M. C., Davies, R. L., Fogarty, L., Goodsall, T., Houghton, R. W., Kassin, S. A., Koekemoer, A. M., Lin, L., Moustakas, L. A., Newman, J. A., Salim, S., Salter, G., Tecza, M., Thatte, N., Wang, T., Weiner, B. J., & Willmer, C. N. (2011). Oxford SWIFT integral field spectrograph and multiwavelength observations of the Eagle galaxy at z= 0.77. Monthly Notices of the Royal Astronomical Society, 417(4), 2882-2890. doi:10.1111/j.1365-2966.2011.19449.x
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  The ‘Eagle’ galaxy at a redshift of 0.77 is studied with the Oxford Short Wavelength Integral Field Spectrograph (SWIFT) and multiwavelength data from the All-wavelength Extended Groth strip International Survey (AEGIS). It was chosen from AEGIS because of the bright and extended emission in its slit spectrum. 3D kinematic maps of the Eagle reveal a gradient in velocity dispersion which spans 35–75 ± 10 km s−1 and a rotation velocity of 25 ± 5 km s−1 uncorrected for inclination. Hubble Space Telescope images suggest it is close to face-on. In comparison with galaxies from AEGIS at similar redshifts, the Eagle is extremely bright and blue in the rest-frame optical, highly star forming, dominated by unobscured star formation and has a low metallicity for its size. This is consistent with its selection. The Eagle is likely undergoing a major merger and is caught in the early stage of a starburst when it has not yet experienced metal enrichment or formed the mass of dust typically found in star-forming galaxies.
• Bundy, K., Conselice, C. J., Cooper, M. C., Grutzbauch, R., Skibba, R. A., Varela, J. A., & Willmer, C. N. (2011). How does galaxy environment matter? The relationship between galaxy environments, colour and stellar mass at 0.4 < z < 1 in the Palomar/DEEP2 survey. Monthly Notices of the Royal Astronomical Society, 411(2), 929-946. doi:10.1111/j.1365-2966.2010.17727.x
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  We present a study characterizing the environments of galaxies in the redshift range of 0.4 < z < 1 based on data from the POWIR near-infrared imaging and DEEP2 spectroscopic redshift surveys, down to a stellar mass of log M*= 10.25 M⊙. Galaxy environments are measured in terms of nearest-neighbour densities as well as fixed aperture densities and kinematical and dynamical parameters of neighbour galaxies within a radius of 1 h−1 Mpc. We disentangle the correlations between galaxy stellar mass, galaxy colour and galaxy environment, using not only galaxy number densities, but also other environmental characteristics such as velocity dispersion, mean harmonic radius and crossing time. We find that galaxy colour and the fraction of blue galaxies depends very strongly on stellar mass at 0.4 < z < 1, while a weak additional dependence on local number densities is in place at lower redshifts (0.4 < z < 0.7). This environmental influence is most visible in the colours of intermediate-mass galaxies (10.5 < log M* < 11), whereas colours of lower- and higher-mass galaxies remain largely unchanged with redshift and environment. At a fixed stellar mass, the colour–density relation almost disappears, while the colour–stellar mass relation is present at all local densities. We find a weak correlation between stellar mass and environment at intermediate redshifts, which contributes to the overall colour–density relation. We furthermore do not find a significant correlation between galaxy colour and virial mass, i.e. parent dark matter halo mass. Galaxy stellar mass thus appears to be the crucial defining parameter for intrinsic galaxy properties such as ongoing star formation and colour.
• Coil, A. L., Cooper, M. C., Cooper, M. C., Georgakakis, A., Juneau, S., Kocevski, D. D., Koo, D. C., Nandra, K., Rosario, D. J., Trump, J. R., & Willmer, C. N. (2011). Observational constraints on the physics behind the evolution of active galactic nuclei since z∼ 1. Monthly Notices of the Royal Astronomical Society, 418(4), 2590-2603. doi:10.1111/j.1365-2966.2011.19650.x
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  We explore the evolution with redshift of the rest-frame colours and space densities of active galactic nuclei (AGN) hosts (relative to normal galaxies) to shed light on the dominant mechanism that triggers accretion on to supermassive black holes as a function of cosmic time. Data from serendipitous wide-area XMM surveys of the Sloan Digital Sky Survey (SDSS) footprint (XMM/SDSS; Needles in the Haystack Survey) are combined with Chandra deep observations in the All-wavelength Extended Groth Strip International Survey (AEGIS), GOODS-North and GOODS-South to compile uniformly selected samples of moderate-luminosity X-ray AGN [LX(2–10 keV) = 1041–1044 erg s−1] at redshifts 0.1, 0.3 and 0.8. It is found that the fraction of AGN hosted by red versus blue galaxies does not change with redshift. Also, the X-ray luminosity density associated with either red or blue AGN hosts remains nearly constant since z= 0.8. X-ray AGN represent a roughly fixed fraction of the space density of galaxies of given optical luminosity at all redshifts probed by our samples. In contrast the fraction of X-ray AGN among galaxies of a given stellar mass decreases with decreasing redshift. These findings suggest that the same process or combination of processes for fuelling supermassive black holes is in operation in the last 5 Gyr of cosmic time. The data are consistent with a picture in which the drop of the accretion power during that period (1 dex since z= 0.8) is related to the decline of the space density of available AGN hosts, as a result of the evolution of the specific star formation rate of the overall galaxy population. Scenarios which attribute the evolution of moderate-luminosity AGN since z≈ 1 to changes in the suppermassive black hole accretion mode are not favoured by our results.
• Egami, E., Finkelstein, S. L., Finkelstein, K. D., Papovich, C., Rieke, M. J., Rigby, J. R., Rudnick, G., Smith, J. T., & Willmer, C. N. (2011). Probing the star formation history and initial mass function of the z ∼ 2.5 lensed galaxy SMM J163554.2+661225 with Herschel. The Astrophysical Journal, 742(2), 108. doi:10.1088/0004-637x/742/2/108
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  We present the analysis of Herschel Spectral and Photometric Imaging Receiver far-infrared (FIR) observations of the z = 2.515 lensed galaxy SMM J163554.2+661225. Combining new 250, 350, and 500 μm observations with existing data, we make an improved fit to the FIR spectral energy distribution of this galaxy. We find a total infrared (IR) luminosity of L(8-1000 μm) = 6.9 ± 0.6 × 1011 L ☉, a factor of three more precise over previous L IR estimates for this galaxy, and one of the most accurate measurements for any galaxy at these redshifts. This FIR luminosity implies an unlensed star formation rate (SFR) for this galaxy of 119 ± 10 M ☉ yr–1, which is a factor of 1.9 ± 0.35 lower than the SFR derived from the nebular Paα emission line (a 2.5σ discrepancy). Both SFR indicators assume an identical Salpeter initial mass function (IMF) with slope Γ = 2.35 over a mass range of 0.1-100 M ☉; thus this discrepancy suggests that more ionizing photons may be necessary to account for the higher Paα-derived SFR. We examine a number of scenarios and find that the observations can be explained with a varying star formation history (SFH) due to an increasing SFR, paired with a slight flattening of the IMF. If the SFR is constant in time, then larger changes need to be made to the IMF by either increasing the upper mass cutoff to ~200 M ☉, or a flattening of the IMF slope to 1.9 ± 0.15, or a combination of the two. These scenarios result in up to double the number of stars with masses above 20 M ☉, which produce the requisite increase in ionizing photons over a Salpeter IMF with a constant SFH.
• Magnelli, B., Elbaz, D., Dickinson, M., Frayer, D. T., Willmer, C. N., Borgne, D. L., & Chary, R. R. (2011). Evolution of the dusty infrared luminosity function from z = 0 to z = 2.3 using observations from Spitzer. Astronomy and Astrophysics, 528(Issue), 1-18. doi:10.1051/0004-6361/200913941
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  Aims. We derive the evolution of the infrared luminosity function (LF) over the last 4/5ths of cosmic time using deep 24 and 70 μm imaging of the GOODS North and South fields. Methods. We use an extraction technique based on prior source positions at shorter wavelengths to build the 24 and 70 μm source catalogs. The majority (93%) of the sources have a spectroscopic (39%) or a photometric redshift (54%) and, in our redshift range of interest (i.e., 1.3 < z < 2.3) ~20% of the sources have a spectroscopic redshift. To extend our study to lower 70 μm luminosities we perform a stacking analysis and we characterize the observed L_(24/(1 + z)) vs. L_(70/(1 + z)) correlation. Using spectral energy distribution (SED) templates which best fit this correlation, we derive the infrared luminosity of individual sources from their 24 and 70 μm luminosities. We then compute the infrared LF at z ~ 1.55 ± 0.25 and z ~ 2.05 ± 0.25. Results. We observe the break in the infrared LF up to z ~ 2.3. The redshift evolution of the infrared LF from z = 1.3 to z = 2.3 is consistent with a luminosity evolution proportional to (1 + z)^(1.0 ± 0.9) combined with a density evolution proportional to (1 + z)^9−1.1 ± 1.5). At z ~ 2, luminous infrared galaxies (LIRGs: 10^(11)L_⊙ < L_(IR) < 10^(12) L_⊙) are still the main contributors to the total comoving infrared luminosity density of the Universe. At z ~ 2, LIRGs and ultra-luminous infrared galaxies (ULIRGs: 10^(12)L_⊙ < L_(IR)) account for ~49% and ~17% respectively of the total comoving infrared luminosity density of the Universe. Combined with previous results using the same strategy for galaxies at z < 1.3 and assuming a constant conversion between the infrared luminosity and star-formation rate (SFR) of a galaxy, we study the evolution of the SFR density of the Universe from z = 0 to z = 2.3. We find that the SFR density of the Universe strongly increased with redshift from z = 0 to z = 1.3, but is nearly constant at higher redshift out to z = 2.3. As part of the online material accompanying this article, we present source catalogs at 24 μm and 70 μm for both the GOODS-North and -South fields.
• Tripp, T. M., Meiring, J. D., Prochaska, J. X., Willmer, C. N., Howk, J. C., Werk, J. K., Jenkins, E. B., Bowen, D. V., Lehner, N., Sembach, K. R., Thom, C., & Tumlinson, J. (2011). The hidden mass and large spatial extent of a post-starburst galaxy outflow.. Science (New York, N.Y.), 334(6058), 952-5. doi:10.1126/science.1209850
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  Outflowing winds of multiphase plasma have been proposed to regulate the buildup of galaxies, but key aspects of these outflows have not been probed with observations. By using ultraviolet absorption spectroscopy, we show that "warm-hot" plasma at 10(5.5) kelvin contains 10 to 150 times more mass than the cold gas in a post-starburst galaxy wind. This wind extends to distances > 68 kiloparsecs, and at least some portion of it will escape. Moreover, the kinematical correlation of the cold and warm-hot phases indicates that the warm-hot plasma is related to the interaction of the cold matter with a hotter (unseen) phase at >>10(6) kelvin. Such multiphase winds can remove substantial masses and alter the evolution of post-starburst galaxies.
• Willmer, C. N., Smith, J. T., Egami, E., Finkelstein, S. L., Papovich, C., Rieke, M. J., Rigby, J. R., Rudnick, G., & Smith, J. D. (2011). Erratum: "Paschen-α Emission in the Gravitationally Lensed Galaxy SMM J163554.2+661225" (2009, ApJ, 704, 1506). The Astrophysical Journal, 742(2), 133. doi:10.1088/0004-637x/742/2/133
• Aird, J., Ashby, M. L., Barmby, P., Coil, A. L., Georgakakis, A., Huang, J. S., Koekemoer, A. M., Laird, E. S., Nandra, K., Steidel, C. C., & Willmer, C. N. (2010). The evolution of the hard X-ray luminosity function of AGN. Monthly Notices of the Royal Astronomical Society, 401(4), 2531-2551. doi:10.1111/j.1365-2966.2009.15829.x
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  We present new observational determinations of the evolution of the 2–10 keV X-ray luminosity function (XLF) of active galactic nuclei (AGN). We utilize data from a number of surveys including both the 2 Ms Chandra Deep Fields and the AEGIS-X 200 ks survey, enabling accurate measurements of the evolution of the faint end of the XLF. We combine direct, hard X-ray selection and spectroscopic follow-up or photometric redshift estimates at z 50 per cent of black hole growth takes place at z > 1 , with around half in L_X < 10^(44) erg s^(−1) AGN.
• Bond, N. A., Choi, E., Coil, A. L., Davis, M., Strauss, M. A., & Willmer, C. N. (2010). Tracing the filamentary structure of the galaxy distribution at z∼0.8. Monthly Notices of the Royal Astronomical Society, 406(1), 320-328. doi:10.1111/j.1365-2966.2010.16707.x
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  We study filamentary structure in the galaxy distribution at z ∼ 0.8 using data from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Redshift Survey and its evolution to z ∼ 0.1 using data from the Sloan Digital Sky Survey (SDSS). We trace individual filaments for both surveys using the Smoothed Hessian Major Axis Filament Finder, an algorithm which employs the Hessian matrix of the galaxy density field to trace the filamentary structures in the distribution of galaxies. We extract 33 subsamples from the SDSS data with a geometry similar to that of DEEP2. We find that the filament length distribution has not significantly changed since z ∼ 0.8, as predicted in a previous study using a Λ cold dark matter cosmological N-body simulation. However, the filament width distribution, which is sensitive to the non-linear growth of structure, broadens and shifts to smaller widths for smoothing length-scales of 5―10 h ―1 Mpc from z ∼ 0.8 to 0.1, in accord with N-body simulations.
• Brodwin, M., Dunlop, J. S., Farrah, D., Finkelstein, S. L., Finkelstein, K. D., Khan, S. A., Lotz, J. M., Mccarthy, P. J., Mclure, R. J., Momcheva, I., Pacaud, F., Papovich, C., Pierre, M., Rieke, M. J., Rudnick, G., Sivanandam, S., Tran, K. H., & Willmer, C. N. (2010). A SPITZER-SELECTED GALAXY CLUSTER AT z = 1.62. The Astrophysical Journal, 716(2), 1503-1513. doi:10.1088/0004-637x/716/2/1503
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  We report the discovery of a galaxy cluster at z = 1.62 located in the Spitzer Wide-Area Infrared Extragalactic survey XMM-LSS field. This structure was selected solely as an overdensity of galaxies with red Spitzer/Infrared Array Camera colors, satisfying ([3.6] - [4.5]){sub AB}> - 0.1 mag. Photometric redshifts derived from the Subaru XMM Deep Survey (BViz bands), the UKIRT Infrared Deep Survey-Ultra-Deep Survey (UKIDSS-UDS, JK bands), and from the Spitzer Public UDS survey (3.6-8.0 {mu}m) show that this cluster corresponds to a surface density of galaxies at z {approx} 1.6 that is >20{sigma} above the mean at this redshift. We obtained optical spectroscopic observations of galaxies in the cluster region using IMACS on the Magellan telescope. We measured redshifts for seven galaxies in the range z = 1.62-1.63 within 2.8 arcmin ( 1.7 mag. The photometric-redshift probability distributionsmore » for the red galaxies are strongly peaked at z = 1.62, coincident with the spectroscopically confirmed galaxies. The rest-frame (U - B) color and scatter of galaxies on the red sequence are consistent with a mean luminosity-weighted age of 1.2 {+-} 0.1 Gyr, yielding a formation redshift z-bar{sub f}=2.35{+-}0.10, and corresponding to the last significant star formation period in these galaxies.« less
• Brodwin, M., Dunlop, J. S., Farrah, D., Finkelstein, S. L., Finkelstein, K. D., Lotz, J. M., Mclure, R. J., Momcheva, I., Papovich, C., Saintonge, A., Tran, K. H., & Willmer, C. N. (2010). Reversal of fortune: confirmation of an increasing star formation-density relation in a cluster at z = 1.62. The Astrophysical Journal, 719(2), L126-L129. doi:10.1088/2041-8205/719/2/l126
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  We measure the rest-frame colors (dust-corrected), infrared luminosities, star formation rates, and stellar masses of 92 galaxies in a Spitzer-selected cluster at z = 1.62. By fitting spectral energy distributions (SEDs) to 10-band photometry (0.4µm 10 11 L� , and these IR luminous members follow the same trend of increasing star formation with stellar mass that is observed in the field at z � 2. Using rates derived from both the 24µm imaging and SED fitting, we find that the relative fraction of star-forming members triples from the lowest to highest galaxy density regions, e .g. the IR luminous fraction increases from � 8% at �� 10 gal Mpc -2 to � 25% at �& 100 gal Mpc -2 . The observed increase is a reversal of the well-documented trend at z < 1 and signals that we have reached the epoch when massive cluster galaxies are still forming a substantial fraction of their stars. Subject headings:galaxies: evolution - galaxies: starburst - galaxies: clus ters: individual (ClG J0218.3-0510) - infrared: galaxies
• Bundy, K., Coil, A. L., Faber, S. M., Laird, E. S., Lotz, J. M., Pierce, C. M., Primack, J. R., Rosario, D. J., Salim, S., & Willmer, C. N. (2010). Host galaxy colour gradients and accretion disc obscuration in AEGIS z ∼ 1 X-ray-selected active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 408(1), 139-156. doi:10.1111/j.1365-2966.2010.17136.x
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  We describe the effect of active galactic nucleus (AGN) light on host galaxy optical and UV-optical colours, as determined from X-ray-selected AGN host galaxies at z ∼ 1, and compare the AGN host galaxy colours to those of a control sample matched to the AGN sample in both redshift and stellar mass. We identify as X-ray-selected AGNs 8.7 +4 ―3 per cent of the red-sequence control galaxies, 9.8 ± 3 per cent of the blue-cloud control galaxies and 14.7 +4 ―3 per cent of the green-valley control galaxies. The nuclear colours of AGN hosts are generally bluer than their outer colours, while the control galaxies exhibit redder nuclei. AGNs in blue-cloud host galaxies experience less X-ray obscuration, while AGNs in red-sequence hosts have more, which is the reverse of what is expected from general considerations of the interstellar medium. Outer and integrated colours of AGN hosts generally agree with the control galaxies, regardless of X-ray obscuration, but the nuclear colours of unobscured AGNs are typically much bluer, especially for X-ray luminous objects. Visible point sources are seen in many of these, indicating that the nuclear colours have been contaminated by AGN light and that obscuration of the X-ray radiation and visible light are therefore highly correlated. Red AGN hosts are typically slightly bluer than red-sequence control galaxies, which suggests that their stellar populations are slightly younger. We compare these colour data to current models of AGN formation. The unexpected trend of less X-ray obscuration in blue-cloud galaxies and more in red-sequence galaxies is problematic for all AGN feedback models, in which gas and dust is thought to be removed as star formation shuts down. A second class of models involving radiative instabilities in hot gas is more promising for red-sequence AGNs but predicts a larger number of point sources in red-sequence AGNs than is observed. Regardless, it appears that multiple AGN models are necessary to explain the varied AGN host properties discussed in the current work. Finally, we find that integrated optical and UV - optical colours are not strongly affected by X-ray-selected AGNs except in rare cases (< 10 per cent), where the AGN is very luminous, unobscured and/or visible as a point source.
• Chiueh, T., Coil, A. L., Cooper, M. C., Croton, D. J., Gerke, B. F., Guhathakurta, P., Jian, H., Koo, D. C., Lin, L., Lotz, J. M., Newman, J. A., Patton, D. R., Willmer, C. N., & Yan, R. (2010). Where do Wet, Dry, and Mixed Galaxy Mergers Occur? A Study of the Environments of Close Galaxy Pairs in the DEEP2 Galaxy Redshift Survey. The Astrophysical Journal, 718(2), 1158-1170. doi:10.1088/0004-637x/718/2/1158
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  We study the environments of wet, dry, and mixed galaxy mergers at 0.75 < z < 1.2 using close pairs in the DEEP2 Galaxy Redshift Survey. We find that the typical environment of dry and mixed merger candidates is denser than that of wet mergers, mostly due to the color-density relation. While the galaxy companion rate (Nc ) is observed to increase with overdensity, using N-body simulations, we find that the fraction of pairs that will eventually merge decreases with the local density, predominantly because interlopers are more common in dense environments. After taking into account the merger probability of pairs as a function of local density, we find only marginal environment dependence of the galaxy merger rate for wet mergers. On the other hand, the dry and mixed merger rates increase rapidly with local density due to the increased population of red galaxies in dense environments, implying that the dry and mixed mergers are most effective in overdense regions. We also find that the environment distribution of K+A galaxies is similar to that of wet mergers alone and of wet+mixed mergers, suggesting a possible connection between K+A galaxies and wet and/or wet+mixed mergers. Based on our results, we therefore expect that the properties, including structures and masses, of red-sequence galaxies should be different between those in underdense regions and those in overdense regions since the dry mergers are significantly more important in dense environments. We conclude that, as early as z ~ 1, high-density regions are the preferred environment in which dry mergers occur, and that present-day red-sequence galaxies in overdense environments have, on average, undergone 1.2 ? 0.3 dry mergers since this time, accounting for (38 ? 10)% of their mass accretion in the last 8 billion years. The main uncertainty in this finding is the conversion from the pair fraction to the galaxy merger rate, which is possibly as large as a factor of 2. Our findings suggest that dry mergers are crucial in the mass assembly of massive red galaxies in dense environments, such as brightest cluster galaxies in galaxy groups and clusters.
• Symeonidis, M., Georgakakis, A., Harker, J., Laird, E. S., Page, M. J., Willmer, C. N., & Rosario, D. J. (2010). The central energy source of 70 μm-selected galaxies: starburst or AGN?. Monthly Notices of the Royal Astronomical Society, 403(3), 1474-1490. doi:10.1111/j.1365-2966.2009.16214.x
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  We present the first active galactic nuclei (AGN) census in a sample of 61 galaxies selected at 70 mu m, a wavelength which should strongly favour the detection of star-forming systems. For the purpose of this study, we take advantage of deep Chandra X-ray and Spitzer infrared (3.6-160 mu m) data, as well as optical spectroscopy and photometry from the Deep Extragalactic Evolutionary Probe 2 (DEEP 2) survey for the Extended Groth Strip (EGS) field, as part of the All-Wavelength Extended Groth Strip International Survey. We investigate spectral line diagnostics ([O iii]/H beta and [Ne iii]/[O ii] ratios, H delta Balmer absorption line equivalent widths and the strength of the 4000 A break), X-ray luminosities and spectral energy distributions (SEDs). We find that the 70-mu m sources are undergoing starburst (SB) episodes and are therefore characterized by a predominance of young stars. In addition, 13 per cent of the sources show AGN signatures and hence potentially host an AGN. When the sample is split into SBs (1010 < L-IR < 1011 L-circle dot), luminous infrared Galaxies (LIRGs; 1011 < L-IR < 1012 L-circle dot) and ultraluminous infrared Galaxies (ULIRGs; 1012 < L-IR < 1013 L-circle dot), the AGN fraction becomes 0, 11 and 23 per cent, respectively, showing an increase with total infrared luminosity. However, by examining the sources' panchromatic SEDs, we conclude that although the AGN is energetically important in 1 out of 61 objects all 70-mu m-selected galaxies are primarily powered by star formation. When compared to a sample of DEEP 2 galaxies in the same redshift range and with similar optical colours, we find that the 70-mu m population is characterized by younger stellar ages and a higher AGN incidence, indicating that strongly star-forming populations might be a key in studying the relationship between black hole and stellar growth.
• Willmer, C. N., Bundy, K., Coil, A. L., Conselice, C. J., Cooper, M. C., Croton, D. J., Davis, M., Faber, S. M., Gerke, B. F., Guhathakurta, P., Koo, D. C., Lin, L., Newman, J. A., Weiner, B. J., & Yan, R. (2010). Absence of evidence is not evidence of absence: the colour–density relation at fixed stellar mass persists to z∼ 1. Monthly Notices of the Royal Astronomical Society, 409(1), 337-345. doi:10.1111/j.1365-2966.2010.17312.x
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  We use data drawn from the DEEP2 Galaxy Redshift Survey to investigate the relationship between local galaxy density, stellar mass and rest-frame galaxy colour. At z∼ 0.9, we find that the shape of the stellar mass function at the high-mass [ log 10(M*/h−2 M⊙) > 10.1] end depends on the local environment, with high-density regions favouring more massive systems. Accounting for this stellar mass–environment relation (i.e. working at fixed stellar mass), we find a significant colour–density relation for galaxies with 10.6 1.
• Aird, J. A., Barmby, P., Coil, A. L., Conselice, C. J., Davis, M., Faber, S. M., Fazio, G. G., Georgakakis, A., Guhathakurta, P., Koo, D. C., Laird, E. S., Nandra, K., Sarajedini, V. L., & Willmer, C. N. (2009). AEGIS-X: THE CHANDRA DEEP SURVEY OF THE EXTENDED GROTH STRIP. Astrophysical Journal Supplement Series, 180(1), 102-116. doi:10.1088/0067-0049/180/1/102
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  We present the AEGIS-X survey, a series of deep Chandra ACIS-I observations of the Extended Groth Strip. The survey comprises pointings at eight separate positions, each with nominal exposure of 200 ks, covering a total area of approximately 0.67 deg2 in a strip of length 2 degrees. We describe in detail an updated version of our data reduction and point-source-detection algorithms used to analyze these data. A total of 1325 band-merged sources have been found to a Poisson probability limit of 4 × 10–6, with limiting fluxes of 5.3 × 10–17 erg cm2 s–1 in the soft (0.5-2 keV) band and 3.8 × 10–16 erg cm–2 s–1 in the hard (2-10 keV) band. We present simulations verifying the validity of our source-detection procedure and showing a very small,
• Blanton, M. R., Coil, A. L., Cooper, M. C., Dave, R., Hogg, D. W., Holden, B. P., Jonsson, P., Kassin, S. A., Lotz, J. M., Moustakas, J., Newman, J. A., Prochaska, J. X., Teuben, P., Tremonti, C., Weiner, B. J., & Willmer, C. N. (2009). Astronomical Software Wants To Be Free: A Manifesto. Astrophysics, 2010.
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  Author(s): Weiner, Benjamin J; Blanton, Michael R; Coil, Alison L; Cooper, Michael C; Dave, Romeel; Hogg, David W; Holden, Bradford P; Jonsson, Patrik; Kassin, Susan A; Lotz, Jennifer M; Moustakas, John; Newman, Jeffrey A; Prochaska, JX; Teuben, Peter J; Tremonti, Christy A; Willmer, Christopher NA | Abstract: Astronomical software is now a fact of daily life for all hands-on members of our community. Purpose-built software for data reduction and modeling tasks becomes ever more critical as we handle larger amounts of data and simulations. However, the writing of astronomical software is unglamorous, the rewards are not always clear, and there are structural disincentives to releasing software publicly and to embedding it in the scientific literature, which can lead to significant duplication of effort and an incomplete scientific record. We identify some of these structural disincentives and suggest a variety of approaches to address them, with the goals of raising the quality of astronomical software, improving the lot of scientist-authors, and providing benefits to the entire community, analogous to the benefits provided by open access to large survey and simulation datasets. Our aim is to open a conversation on how to move forward. We advocate that: (1) the astronomical community consider software as an integral and fundable part of facility construction and science programs; (2) that software release be considered as integral to the open and reproducible scientific process as are publication and data release; (3) that we adopt technologies and repositories for releasing and collaboration on software that have worked for open-source software; (4) that we seek structural incentives to make the release of software and related publications easier for scientist-authors; (5) that we consider new ways of funding the development of grass-roots software; (6) and that we rethink our values to acknowledge that astronomical software development is not just a technical endeavor, but a fundamental part of our scientific practice.
• Borgne, D. L., Chary, R. R., Dickinson, M., Elbaz, D., Frayer, D. T., Magnelli, B., & Willmer, C. N. (2009). The 0.4 < z < 1.3 star formation history of the Universe as viewed in the far-infrared. Astronomy and Astrophysics, 496(1), 57-75. doi:10.1051/0004-6361:200811443
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  Aims. We use the deepest existing mid- and far-infrared observations (reaching ∼3 mJy at 70 μm) obtained with Spitzer in the Great Observatories Origins Deep Survey (GOODS) and Far Infrared Deep Extragalactic Legacy survey (FIDEL) fields to derive the evolution of the rest-frame 15 μm, 35 μm, and total infrared luminosity functions of galaxies spanning z < 1.3. We thereby quantify the fractional contribution of infrared luminous galaxies to the comoving star formation rate density over this redshift range. In comparison with previous studies, the present one takes advantage of deep 70 μm observations that provide a more robust infrared luminosity indicator than 24 μm affected by the emission of PAHs at high redshift (z ∼ 1), and we use several independent fields to control cosmic variance. Methods. We used a new extraction technique based on the well-determined positions of galaxies at shorter wavelengths to extract the 24 and 70 μm flux densities of galaxies. It is found that sources separated by a minimum of 0.5 x FWHM are deblended by this technique, which facilitates multi-wavelength associations of counterparts. Using a combination of photometric and spectroscopic redshifts that exist for ∼80% of the sources in our sample, we are able to estimate the rest-frame luminosities of galaxies at 15 μm and 35 μm. By complementing direct detections with a careful stacking analysis, we measured the mid- and far-infrared luminosity functions of galaxies over a factor ∼100 in luminosity (1011 L ⊙
• Chen, Y., Wild, V., Kauffmann, G., Blaizot, J., Davis, M., Wang, J., Noeske, K. G., & Willmer, C. N. (2009). Constraints on the star formation histories of galaxies from z∼ 1 to 0. Monthly Notices of the Royal Astronomical Society, 393(2), 406-418. doi:10.1111/j.1365-2966.2008.14247.x
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  We present a new method to estimate the average star formation rate per unit stellar mass (SSFR) of a stacked population of galaxies. We combine the spectra of 600-1000 galaxies with similar stellar masses and parametrize the star formation history of this stacked population using a set of exponentially declining functions. The strength of the hydrogen Balmer absorption-line series in the rest-frame wavelength range 3750-4150 A is used to constrain the SSFR by comparing with a library of models generated using the BC03 stellar population code. Our method, based on a principal component analysis, can be applied in a consistent way to spectra drawn from local galaxy surveys and from surveys at z ∼ 1, and is only weakly influenced by attenuation due to dust. We apply our method to galaxy samples drawn from Sloan Digital Sky Survey and DEEP2 to study the mass-dependent growth of galaxies from z ∼ 1 to 0. We find that (i) high-mass galaxies have lower SSFRs than low-mass galaxies and (ii) the average SSFR has decreased from z = 1 to 0 by a factor of ∼3-4, independent of galaxy mass. Additionally, at z ∼ 1, our average SSFRs are a factor of 2-2.5 lower than those derived from multiwavelength photometry using similar data sets. We then compute the average time [in units of the Hubble time, t H (z)] needed by galaxies of a given mass to form their stars at their current rate. At both z = 0 and 1, this time-scale decreases strongly with stellar mass from values close to unity for galaxies with masses ∼10 10 M ⊙ , to more than 10 for galaxies more massive than 10 11 M ⊙ . Our results are in good agreement with models in which active galactic nuclei feedback is more efficient at preventing gas from cooling and forming stars in high-mass galaxies.
• Coil, A. L., Cooper, M. C., Croton, D. J., Davis, M., Georgakakis, A., Koo, D. C., Laird, E. S., Nandra, K., Newman, J. A., Weiner, B. J., Willmer, C. N., & Yan, R. (2009). AEGIS: THE CLUSTERING OF X-RAY ACTIVE GALACTIC NUCLEUS RELATIVE TO GALAXIES AT z ∼ 1. The Astrophysical Journal, 701(2), 1484-1499. doi:10.1088/0004-637x/701/2/1484
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  We measure the clustering of nonquasar X-ray active galactic nucleus (AGN) at z = 0.7-1.4 in the AEGIS field. Using the cross-correlation of 113 Chandra-selected AGN, with a median log L X = 42.8 erg s–1, with ~5000 DEEP2 galaxies, we find that the X-ray AGNs are fitted by a power law with a clustering scale length of r 0 = 5.95 ± 0.90 h –1 Mpc and slope γ = 1.66 ± 0.22. X-ray AGNs have a similar clustering amplitude as red, quiescent and "green" transition galaxies at z ~ 1 and are significantly more clustered than blue, star-forming galaxies. The X-ray AGN clustering strength is primarily determined by the host galaxy color; AGNs in red host galaxies are significantly more clustered than AGNs in blue host galaxies, with a relative bias that is similar to that of red to blue DEEP2 galaxies. We detect no dependence of clustering on optical brightness, X-ray luminosity, or hardness ratio within the ranges probed here. We find evidence for galaxies hosting X-ray AGN to be more clustered than a sample of galaxies with matching joint optical color and magnitude distributions. This implies that galaxies hosting X-ray AGN are more likely to reside in groups and more massive dark matter halos than galaxies of the same color and luminosity without an X-ray AGN. In comparison to optically selected quasars in the DEEP2 fields, we find that X-ray AGNs at z ~ 1 are more clustered than optically selected quasars (with a 2.6σ significance) and therefore may reside in more massive dark matter halos. Our results are consistent with galaxies undergoing a quasar phase while in the blue cloud before settling on the red sequence with a lower-luminosity X-ray AGN, if they are similar objects at different evolutionary stages.
• Coil, A. L., Cooper, M. C., Davis, M., Gerke, B. F., Jeltema, T. E., Laird, E. S., Nandra, K., Newman, J. A., & Willmer, C. N. (2009). Groups of galaxies in AEGIS: the 200-ks Chandra extended X-ray source catalogue. Monthly Notices of the Royal Astronomical Society, 399(2), 715-727. doi:10.1111/j.1365-2966.2009.15377.x
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  We present the discovery of seven X-ray emitting groups of galaxies selected as extended X-ray sources in the 200-ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). In addition, we report on active galactic nucleus (AGN) activity associated with these systems. For the six extended sources which lie within the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Galaxy Redshift Survey coverage, we identify optical counterparts and determine velocity dispersions. In particular, we find three massive high-redshift groups at z > 0.7, one of which is at z = 1.13, the first X-ray detections of spectroscopically selected DEEP2 groups. We also present a first look at the L x -T, L X -σ and σ-T scaling relations for high-redshift massive groups. We find that the properties of these X-ray selected systems agree well with the scaling relations of similar systems at low redshift, although there are X-ray undetected groups in the DEEP2 catalogue with similar velocity dispersions. The other three X-ray groups with identified redshifts are associated with lower mass groups at z ~ 0.07 and together form part of a large structure or 'supergroup' in the southern portion of the AEGIS field. Similar to other X-ray-luminous groups, all of the low-redshift systems are centred on massive elliptical galaxies, and all of the high-redshift groups have likely central galaxies or galaxy pairs. Interestingly, the central galaxies in the highest redshift system show indications of ongoing star formation. All of the central group galaxies host X-ray point sources, radio sources and/or show optical AGN emission. Particularly interesting examples of central AGN activity include a bent-double radio source plus X-ray point source at the centre of a group at z = 0.74, extended radio and double X-ray point sources associated with the central galaxy in the lowest redshift group at z = 0.066, and a bright green valley galaxy (part of a pair) in the z = 1.13 group which shows optical AGN emission lines.
• Devereux, N., Willner, S. P., Ashby, M. L., Willmer, C. N., & Hriljac, P. (2009). Nearby galaxies in the 2 μm all sky survey. i.k-band luminosity functions. The Astrophysical Journal, 702(2), 955-969. doi:10.1088/0004-637x/702/2/955
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  Differential Ks -band luminosity functions (LFs) are presented for a complete sample of 1613 nearby bright galaxies segregated by visible morphology. The LF for late-type spirals follows a power law that rises toward low luminosities whereas the LFs for ellipticals, lenticulars, and bulge-dominated spirals are peaked and decline toward both higher and lower luminosities. Each morphological type (E, S0, S0/a-Sab, Sb-Sbc, Sc-Scd) contributes approximately equally to the overall Ks -band luminosity density of galaxies in the local universe. Type averaged bulge/disk ratios are used to subtract the disk component leading to the prediction that the Ks -band LF for bulges is bimodal with ellipticals dominating the high luminosity peak, comprising 60% of the bulge luminosity density in the local universe with the remaining 40% contributed by lenticulars and the bulges of spirals. Overall, bulges contribute 30% of the galaxy luminosity density at Ks in the local universe with spiral disks making up the remainder. If bulge luminosities indicate central black hole (BH) masses, then our results predict that the BH mass function is also bimodal.
• Egami, E., Finkelstein, S. L., Floc'h, E. L., Papovich, C., Rieke, M. J., Rigby, J. R., Rudnick, G., & Willmer, C. N. (2009). TURNING BACK THE CLOCK: INFERRING THE HISTORY OF THE EIGHT O'CLOCK ARC*. The Astrophysical Journal, 700(1), 376-386. doi:10.1088/0004-637x/700/1/376
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  We present the results from an optical and near-infrared (NIR) spectroscopic study of the ultraviolet-luminous z = 2.73 galaxy, the 8 o'clock arc. Due to gravitational lensing, this galaxy is magnified by a factor of ? > 10, allowing in-depth measurements which are usually unfeasible at such redshifts. In the optical spectra, we measured the systemic redshift of the galaxy, z = 2.7322? 0.0012, using stellar photospheric lines. This differs from the redshift of absorption lines in the interstellar medium, z = 2.7302 ? 0.0006, implying gas outflows on the order of 160 km s?1. With H- and K-band NIR spectra, we have measured nebular emission lines of H?, H?, H?, [N II], and [O III], which have a redshift z = 2.7333 ? 0.0001, consistent with the derived systemic redshift. From the Balmer decrement, we measured the dust extinction in this galaxy to be A 5500 = 1.17 ? 36 mag. Correcting the H? line flux for dust extinction as well as the assumed lensing factor, we measure a star formation rate (SFR) of ~270 M ? yr?1, which is higher than ~85% of star-forming galaxies at z ~ 2-3. Using combinations of all detected emission lines, we find that the 8 o'clock arc has a gas-phase metallicity of ~0.8 Z ?, showing that enrichment at high redshift is not rare, even in blue, star-forming galaxies. Studying spectra from two of the arc components separately, we find that one component dominates both the dust extinction and SFR, although the metallicities between the two components are similar. We derive the mass via stellar population modeling, and find that the arc has a total stellar mass of ~4.2 ? 1011 M ?, which falls on the mass-metallicity relation at z ~ 2. Finally, we estimate the total gas mass, and find it to be only ~12% of the stellar mass, implying that the 8 o'clock arc is likely nearing the end of a starburst.
• Egami, E., Finkelstein, S. L., Papovich, C., Rieke, M. J., Rigby, J. R., Rudnick, G., Smith, J. T., & Willmer, C. N. (2009). PASCHEN-α EMISSION IN THE GRAVITATIONALLY LENSED GALAXY SMM J163554.2+661225*. The Astrophysical Journal, 704(2), 1506-1518. doi:10.1088/0004-637x/704/2/1506
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  We report the detection of the Paalpha emission line in the z = 2.515 galaxy SMM J163554.2+661225 using Spitzer spectroscopy. SMM J163554.2+661225 is a submillimeter-selected infrared-luminous galaxy maintaining a high star formation rate (SFR), with no evidence of an active galactic nucleus from optical or infrared spectroscopy, nor X-ray emission. This galaxy is lensed gravitationally by the cluster Abell 2218, making it accessible to Spitzer spectroscopy. We measure a line luminosity, L(Paalpha) = (2.05 +- 0.33) x 10{sup 42} erg s{sup -1}, corrected for gravitational lensing. Comparing the Halpha and Paalpha luminosities, we derive a nebular extinction, A(V) = 3.6 +- 0.4 mag. The dust-corrected luminosity, L(Paalpha) = (2.57 +- 0.43) x 10{sup 42} erg s{sup -1}, corresponds to an ionization rate, Q {sub 0} = (1.6 +- 0.3) x 10{sup 55} gamma s{sup -1}. The instantaneous SFR is psi = 171 +- 28 M {sub sun} yr{sup -1}, assuming a Salpeter-like initial mass function from 0.1 to 100 M {sub sun} yr{sup -1}. The total IR luminosity derived using 70, 450, and 850 mum data is L{sub IR} = (5-10) x 10{sup 11} L {sub sun}, corrected for gravitational lensing. This corresponds to psi = 90-180 M {sub sun}more » yr{sup -1}, where the upper range is consistent with that derived from the Paalpha luminosity. While the L(8 mum)/L(Paalpha) ratio is consistent with the extrapolated relation observed in local galaxies and star-forming regions, the rest-frame 24 mum luminosity is significantly lower with respect to local galaxies of comparable Paalpha luminosity. Thus, SMM J163554.2+661225 arguably lacks a warmer dust component (T{sub D} approx 70 K), which is associated with deeply embedded star formation, and which contrasts with local galaxies with comparable SFRs. Rather, the starburst in SMM J163554.2+661225 is consistent with star-forming local galaxies with intrinsic luminosities, L{sub IR} approx 10{sup 10} L {sub sun}, but 'scaled up' by a factor of approx10-100.« less
• Faber, S. M., Dickinson, M., Willmer, C. N., Bundy, K., Cattaneo, A., Chapman, S. C., Conselice, C. J., Daddi, E., Dickinson, M., Egami, E., Faber, S. M., Fazio, G. G., Floc'h, E. L., Huang, J. S., Im, M., Koo, D. C., Lai, K., Laird, E. S., Omont, A., , Papovich, C., et al. (2009). INFRARED SPECTROGRAPH SPECTROSCOPY AND MULTI-WAVELENGTH STUDY OF LUMINOUS STAR-FORMING GALAXIES AT z ≃ 1.9. The Astrophysical Journal, 700(1), 183-198. doi:10.1088/0004-637x/700/1/183
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  We analyze a sample of galaxies chosen to have F_(24μm) > 0.5 mJy and satisfy a certain IRAC color criterion. Infrared Spectrograph (IRS) spectra yield redshifts, spectral types, and polycyclic aromatic hydrocarbons (PAH) luminosities, to which we add broadband photometry from optical through IRAC wavelengths, MIPS from 24-160 μm, 1.1 mm, and radio at 1.4 GHz. Stellar population modeling and IRS spectra together demonstrate that the double criteria used to select this sample have efficiently isolated massive star-forming galaxies at z ~ 1.9. This is the first starburst (SB)-dominated ultraluminous infrared galaxies (ULIRG) sample at high redshift with total infrared luminosity measured directly from FIR and millimeter photometry, and as such gives us the first accurate view of broadband spectral energy distributions for SB galaxies at extremely high luminosity and at all wavelengths. Similar broadband data are assembled for three other galaxy samples—local SB galaxies, local active galactic nucleus (AGN)/ULIRGs, and a second 24 μm-luminous z ~ 2 sample dominated by AGN. L_(PAH)/L_(IR) for the new z ~ 2 SB sample is the highest ever seen, some three times higher than in local SBs, whereas in AGNs this ratio is depressed below the SB trend, often severely. Several pieces of evidence imply that AGNs exist in this SB-dominated sample, except two of which even host very strong AGN, while they still have very strong PAH emission. The Advanced Camera for Surveys images show that most objects have very extended morphologies in the rest-frame ultraviolet band, thus extended distribution of PAH molecules. Such an extended distribution prevents further destruction PAH molecules by central AGNs. We conclude that objects in this sample are ULIRGs powered mainly by SB; and the total infrared luminosity density contributed by this type of objects is 0.9-2.6 × 10^7 L_☉ Mpc^(–3).
• Hinz, J. L., Engelbracht, C. W., Floc'h, E. L., Gordon, K. D., Marcillac, D., Rieke, G. H., & Willmer, C. N. (2009). SPITZER OBSERVATIONS OF COLD DUST GALAXIES. The Astronomical Journal, 138(1), 146-158. doi:10.1088/0004-6256/138/1/146
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  We combine new Spitzer Space Telescope observations in the mid-infrared and far-infrared (FIR) with SCUBA 850 μm observations to improve the measurement of dust temperatures, masses, and luminosities for 11 galaxies of the SCUBA Local Universe Galaxy Survey. By fitting dust models we measure typical dust masses of 107.9 M ☉ and dust luminosities of ~1010 L ☉, for galaxies with modest star formation rates. The data presented in this paper combined with previous observations show that cold dust is present in all types of spiral galaxies and is a major contributor to their total luminosity. Because of the lower dust temperature of the SCUBA sources measured in this paper, they have flatter FIR νFν(160 μm)/νFν(850 μm) slopes than the larger Spitzer Infrared Nearby Galaxies Survey (SINGS), the sample that provides the best measurements of the dust properties of galaxies in the nearby universe. The new data presented here added to SINGS extend the parameter space that is well covered by local galaxies, providing a comprehensive set of templates that can be used to interpret the observations of nearby and distant galaxies.
• Avrett, E., Armus, L., Avrett, E. H., Blaylock, M., Carpenter, J. M., Cutri, R. M., Decin, L., Engelbracht, C. W., Gordon, K. D., Gray, R. O., Hinz, J. L., Ogle, P., Rieke, G. H., Su, K. Y., & Willmer, C. N. (2008). Absolute physical calibration in the infrared. The Astronomical Journal, 135(6), 2245-2263. doi:10.1088/0004-6256/135/6/2245
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  We determine an absolute calibration for the Multiband Imaging Photometer for Spitzer 24 μm band and recommend adjustments to the published calibrations for Two Micron All Sky Survey (2MASS), Infrared Array Camera (IRAC), and IRAS photometry to put them on the same scale. We show that consistent results are obtained by basing the calibration on either an average A0V star spectral energy distribution (SED), or by using the absolutely calibrated SED of the Sun in comparison with solar-type stellar photometry (the solar analog method). After the rejection of a small number of stars with anomalous SEDs (or bad measurements), upper limits of ~1.5% root mean square (rms) are placed on the intrinsic infrared (IR) SED variations in both A-dwarf and solar-type stars. These types of stars are therefore suitable as general-purpose standard stars in the IR. We provide absolutely calibrated SEDs for a standard zero magnitude A star and for the Sun to allow extending this work to any other IR photometric system. They allow the recommended calibration to be applied from 1 to 25 μm with an accuracy of ~2%, and with even higher accuracy at specific wavelengths such as 2.2, 10.6, and 24 μm, near which there are direct measurements. However, we confirm earlier indications that Vega does not behave as a typical A0V star between the visible and the IR, making it problematic as the defining star for photometric systems. The integration of measurements of the Sun with those of solar-type stars also provides an accurate estimate of the solar SED from 1 through 30 μm, which we show agrees with theoretical models.
• Borys, C., Egami, E., Fadda, D., Kneib, J. P., Knudsen, K. K., Marcillac, D., Papovich, C., Perez-gonzalez, P. G., Richard, J., Rieke, G. H., Rigby, J. R., Werf, P. V., & Willmer, C. N. (2008). Mid-Infrared Spectroscopy of Lensed Galaxies at 1 < z < 3: The Nature of Sources Near the MIPS Confusion Limit. The Astrophysical Journal, 675(1), 262-280. doi:10.1086/525273
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  We present Spitzer IRS mid-infrared spectra for 15 gravitationally lensed, 24 μm-selected galaxies, and combine the results with four additional very faint galaxies with IRS spectra in the literature. The median intrinsic 24 μm flux density of the sample is 130 μJy, enabling a systematic survey of the spectral properties of the very faint 24 μm sources that dominate the number counts of Spitzer cosmological surveys. Six of the 19 galaxy spectra (32%) show the strong mid-IR continuua expected of AGNs; X-ray detections confirm the presence of AGNs in three of these cases, and reveal AGNs in two other galaxies. These results suggest that nuclear accretion may contribute more flux to faint 24 μm-selected samples than previously assumed. Almost all the spectra show some aromatic (PAH) emission features; the measured aromatic flux ratios do not show evolution from z = 0. In particular, the high signal-to-noise mid-IR spectrum of SMM J163554.2+661225 agrees remarkably well with low-redshift, lower luminosity templates. We compare the rest-frame 8 μm and total infrared luminosities of star-forming galaxies, and find that the behavior of this ratio with total IR luminosity has evolved modestly from z = 2 to z = 0. Since the high aromatic-to-continuum flux ratios in these galaxies rule out a dominant contribution by AGNs, this finding implies systematic evolution in the structure and/or metallicity of infrared sources with redshift. It also has implications for the estimates of star-forming rates inferred from 24 μm measurements, in the sense that at z ~ 2, a given observed frame 24 μm luminosity corresponds to a lower bolometric luminosity than would be inferred from low-redshift templates of similar luminosity at the corresponding rest wavelength.
• Casteels, K., Chiueh, T., Conselice, C. J., Cooper, M. C., Faber, S. M., Hsieh, B. C., Koo, D. C., Lin, L., Lotz, J. M., Newman, J. A., Novak, G. S., Patton, D. R., Weiner, B. J., & Willmer, C. N. (2008). The Redshift Evolution of Wet, Dry, and Mixed Galaxy Mergers from Close Galaxy Pairs in the DEEP2 Galaxy Redshift Survey. The Astrophysical Journal, 681(1), 232-243. doi:10.1086/587928
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  We study the redshift evolution of galaxy pair fractions and merger rates for different types of galaxies using kinematic pairs selected from the DEEP2 Redshift Survey, combined with other surveys at lower redshifts. By parameterizing the evolution of the pair fraction as -->(1 + z)m, we find that the companion rate increases mildly with redshift with -->m = 0.41 ± 0.20 for all galaxies with – -->21 m = 1.27 ± 0.35, while the red companion rate of red galaxies is better fitted with the negative slope -->m = − 0.92 ± 0.59. For the chosen luminosity range, we find that at low redshift the pair fraction within the red sequence exceeds that of the blue cloud, indicating a higher merger probability among red galaxies compared to that among the blue galaxies. With further assumptions on the merger timescale and the fraction of pairs that will merge, the galaxy major merger rates for -->0.1 10−3 h3 Mpc −3 Gyr −1 with a factor of 2 uncertainty. At -->z ~ 1.1, 68% of mergers are wet, 8% of mergers are dry, and 24% of mergers are mixed, compared to 31% wet mergers, 25% dry mergers, and 44% mixed mergers at -->z ~ 0.1. Wet mergers dominate merging events at -->z = 0.2–1.2, but the relative importance of dry and mixed mergers increases over time. About 22%-54% of present-day -->L* galaxies have experienced major mergers since -->z ~ 1.2, depending on the definition of major mergers. Moreover, 24% of the red galaxies at the present epoch have had dry mergers with luminosity ratios between $1t{:}t 4$ --> and $4t{:}t 1$ --> since -->z ~ 1. Our results also suggest that the wet mergers and/or mixed mergers may be partially responsible for producing red galaxies with intermediate masses, while a significant portion of massive red galaxies are assembled through dry mergers at later times.
• Coil, A. L., Conselice, C. J., Cooper, M. C., Davis, M., Faber, S. M., Floc'h, E. L., Guhathakurta, P., Gwyn, S. D., Hopkins, A. M., Huang, J. S., Koo, D. C., Lin, L., Lotz, J. M., Metevier, A. J., Newman, J. A., Noeske, K. G., Papovich, C., Primack, J. R., Rieke, G. H., , Weiner, B. J., et al. (2008). The Evolution of Galaxy Mergers and Morphology at z<1.2 in the Extended Groth Strip. The Astrophysical Journal, 672(1), 177-197. doi:10.1086/523659
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  We present the quantitative rest-frame B morphological evolution and galaxy merger fraction at 0.2 1011 L☉ are disk galaxies, and only ~15% are classified as major merger candidates. Edge-on and dusty disk galaxies (Sb-Ir) are almost a third of the red sequence at z ~ 1.1, while E/S0/Sa make up over 90% of the red sequence at z ~ 0.3. Approximately 2% of our full sample are red mergers. We conclude (1) the merger rate does not evolve strongly between 0.2 < z < 1.2; (2) the decrease in the volume-averaged star formation rate density since z ~ 1 is a result of declining star formation in disk galaxies rather than a disappearing population of major mergers; (3) the build-up of the red sequence at z < 1 can be explained by a doubling in the number of spheroidal galaxies since z ~ 1.2.
• Cooper, M. C., Donley, J. L., Kirby, E. N., Rieke, G. H., Shi, Y., & Willmer, C. N. (2008). Black Hole Accretion in Low-Mass Galaxies since z ~ 1. The Astrophysical Journal, 688(2), 794-806. doi:10.1086/592192
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  We have selected a sample of X-ray-emitting active galactic nuclei (AGNs) in low-mass host galaxies (~5 × 109-2 × 1010 M☉) out to z ~ 1. By comparing to AGNs in more massive hosts, we have found that the AGN spatial number density and the fraction of galaxies hosting AGNs depends strongly on the host mass, with the AGN host mass function peaking at intermediate mass and with the AGN fraction increasing with host mass. AGNs in low-mass hosts show strong cosmic evolution in comoving number density, the fraction of such galaxies hosting active nuclei, and the comoving X-ray energy density. The integrated X-ray luminosity function is used to estimate the amount of the accreted black hole mass in these AGNs and places a strong lower limit of 12% to the fraction of local low-mass galaxies hosting black holes, although a more likely value is probably much higher (>50%) once the heavily obscured objects missed in current X-ray surveys are accounted for.
• Smith, J. D., Willmer, C. N., Engelbracht, C. W., Gordon, K. D., Moustakas, J., Rieke, G. H., Smith, J. D., Vanzi, L., & Werner, M. W. (2008). Erratum: "Metallicity Effects on Dust Properties in Starbursting Galaxies" (ApJ, 678, 804 [2008]). The Astrophysical Journal, 685(1), 678-678. doi:10.1086/590905
• Smith, J. T., Engelbracht, C. W., Gordon, K. D., Moustakas, J., Rieke, G. H., Smith, J. D., Vanzi, L., Werner, M. W., & Willmer, C. N. (2008). Metallicity effects on dust properties in starbursting galaxies. The Astrophysical Journal, 678(2), 804-827. doi:10.1086/529513
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  We present infrared observations of 66 starburst galaxies over the full range of oxygen abundances observed in local star-forming galaxies, from -->12 + log (O/H) = 7.1 to 8.9. The data include imaging and spectroscopy from the Spitzer Space Telescope, supplemented by ground-based near-infrared imaging. We confirm a strong correlation of aromatic emission with metallicity, with a threshold at -->12 + log (O/H) ~ 8. We show that the far-infrared color temperature of the large dust grains increases toward lower metallicity, peaking at a metallicity of 8 before turning over. We compute dust masses and compare them to H I masses from the literature to derive the ratio of atomic gas to dust, which increases by nearly 3 orders of magnitude between solar metallicity and a metallicity of 8, below which it flattens out. The abrupt change in aromatic emission at mid-infrared wavelengths thus appears to be reflected in the far-infrared properties, indicating that metallicity changes affect the composition of the full range of dust grain sizes that dominate the infrared emission. Although the great majority of galaxies show similar patterns of behavior as described above, there are three exceptions, SBS 0335?052E, Haro 11, and SHOC 391. Their infrared SEDs are dominated energetically by the mid-IR near 24 ?m rather than by the 60-200 ?m region. In addition, they have very weak near-infrared outputs and their SEDs are dominated by emission by dust at wavelengths as short as 1.8 ?m. The latter behavior indicates that the dominant star-forming episodes in them are extremely young. The component of the ISM responsible for the usual far-infrared emission appears to be either missing or inefficiently heated in these three galaxies.
• Weiner, B. J., Coil, A. L., Cooper, M. C., Fazio, G. G., Georgakakis, A., Gerke, B. F., Huang, J. S., Koo, D. C., Laird, E. S., Marcillac, D., Nandra, K., Newman, J. A., Papovich, C., Rieke, G. H., Weiner, B. J., Willmer, C. N., & Woo, J. (2008). The Environment on a Few Mpc Scales of Infrared Luminous Galaxies at Redshift z~1. The Astrophysical Journal, 675(2), 1156-1170. doi:10.1086/527031
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  We investigate the environment of infrared-luminous galaxies [ -->LIR(8–1000 μ m) > 1011 L☉]. We focus on the redshift range -->0.7 ≤ z≤ 1, where these galaxies dominate the star formation activity and play a significant role in galaxy evolution. We employ MIPS 24 μm data to identify infrared galaxies in the Extended Groth Strip (EGS). We use a local density indicator to probe the environment on a few Mpc scales and a group member catalog, both of which make use of the DEEP2 spectroscopic redshift catalog, to quantify the environment of these galaxies. We find that the local environment of LIRGs and ULIRGs is intermediate between that of blue and red galaxies. LIRGs and ULIRGs avoid underdense environments and inhabit local environments that are more dense on average than those of other DEEP2 galaxies at similar redshifts. However, when the comparison sample of the non-IR DEEP2 galaxies is restricted to have the same range of stellar mass, color, or luminosity as the IR galaxies, there is no longer any significant difference in environment: the IR galaxies follow the same trends in the color-environment and luminosity-environment relations observed at -->z ~ 1. We also find that about 30% of the LIRGs and ULIRGs belong to groups, associated with a minimum dark matter halo of -->6 × 1012 M☉ h−1. The group members constitute 20% of the sources responsible for the IR star formation rate density and comoving energy density at -->z ~ 1.
• Almaini, O., Coil, A. L., Conselice, C. J., Cooper, M. C., Eisenhardt, P., Foucaud, S., Georgakakis, A., Koekemoer, A. M., Lotz, J. M., Newman, J. A., Noeske, K. G., Weiner, B. J., & Willmer, C. N. (2007). AEGIS: The Diversity of Bright Near-IR Selected Distant Red Galaxies. The Astrophysical Journal, 660(1), L55-L58. doi:10.1086/517921
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  AEGIS: The Diversity of Bright Near-IR Selected Distant Red Galaxies C. J. Conselice 1 , J. A. Newman 2,3 , A. Georgakakis 4 , O. Almaini 1 , A. L. Coil 3,5 , M.C. Cooper 6 , P. Eisenhardt 7 , S. Foucaud 1 , A. Koekemoer 8 , J. Lotz 9 , K. Noeske 10 , B. Weiner 11 , C.N.A Willmer 5 arXiv:astro-ph/0607242 v1 11 Jul 2006 ABSTRACT We use deep and wide near infrared (NIR) imaging from the Palomar telescope combined with DEEP2 spectroscopy and Hubble Space Telescope (HST) and Chandra Space Telescope imaging to investigate the nature of galaxies that are red in NIR colors. We locate these ‘distant red galaxies’ (DRGs) through the color cut (J − K) vega > 2.3 over 0.7 deg 2 , where we find 1010 DRG candidates down to K s = 20.5. We combine 95 high quality spectroscopic redshifts with photometric redshifts from BRIJK photometry to determine the redshift and stellar mass distributions for these systems, and morphological/structural and X-ray properties for 107 DRGs in the Extended Groth Strip. We find that many bright (J − K) vega > 2.3 galaxies with K s 2 systems massive with M ∗ > 10 11 M ⊙ . HST imaging shows that the structural properties and morphologies of DRGs are also diverse, with the majority elliptical/compact School of Physics and Astronomy, University of Nottingham, NG7 2RD, UK Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Hubble Fellow Imperial College, London Stewart Observatory, University of Arizona, Tucson, AZ University of California, Berkeley NASA Jet Propulsion Laboratory, California Institute of Technology Space Telescope Science Institute, Baltimore, MD Goldberg Fellow, National Optical Astronomy Observatory, Tucson, AZ 85726 University of California, Santa Cruz, Santa Cruz, CA Department of Physics, University of Maryland, College Park, MD 20742
• Antonucci, R., Bouwman, J., Hines, D. C., Low, F. J., Ogle, P., Rieke, G. H., Shi, Y., Smith, P. S., & Willmer, C. N. (2007). Aromatic features in agns : Star-forming infrared luminosity function of agn host galaxies. The Astrophysical Journal, 669(2), 841-861. doi:10.1086/521594
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  We describe observations of aromatic features at 7.7 and 11.3 μm in AGNs of three types, including PG, 2MASS, and 3CR objects. The feature has been demonstrated to originate predominantly from star formation. Based on the aromatic-derived star-forming luminosity, we find that the far-IR emission of AGNs can be dominated by either star formation or nuclear emission; the average contribution from star formation is around 25% at 70 and 160 μm. The star-forming infrared luminosity functions of the three types of AGNs are flatter than those of field galaxies, implying that nuclear activity and star formation tend to be enhanced together. The star-forming luminosity function is also a function of the strength of nuclear activity from normal galaxies to the bright quasars, with luminosity functions becoming flatter for more intense nuclear activity. Different types of AGNs show different distributions in the level of star formation activity, with 2MASS > PG > 3CR star formation rates.
• Ashby, M. L., Barmby, P., Coil, A. L., Conselice, C. J., Davis, M., Faber, S. M., Fazio, G. G., Huang, J. S., Ivison, R., Koekemoer, A. M., Lotz, J. M., Miyazaki, S., Newman, J. A., Papovich, C., Rigopoulou, D., Salim, S., Willmer, C. N., Willner, S. P., Wilson, G., & Yan, R. (2007). AEGIS: A PANCHROMATIC STUDY OF IRAC-SELECTED EXTREMELY RED OBJECTS WITH CONFIRMED SPECTROSCOPIC REDSHIFTS. The Astrophysical Journal, 660(1), L59-L63. doi:10.1086/517923
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  We study 87 extremely red objects (EROs), selected both to have color redder than R - [3.6] = 4.0 and to have confirmed spectroscopic redshifts. Together, these two constraints result in this sample populating a fairly narrow redshift range at 0.76 < z < 1.42. The key new ingredient included here is deep Spitzer Space Telescope Infrared Array Camera (IRAC) data. Based on [3.6] - [8.0] color, we demonstrate that it is possible to classify EROs as early-type galaxies, dusty starburst galaxies, or active galactic nuclei (AGNs; power-law types). We present ultraviolet-to-mid-infrared spectral energy distributions (SEDs) and Advanced Camera for Surveys (ACS) images, both of which support our simple IRAC color classification.
• Barmby, P., Bundy, K., Coil, A. L., Conselice, C. J., Cooper, M. C., Davis, M., Ellis, R. S., Faber, S. M., Fazio, G. G., Floc'h, E. L., Guhathakurta, P., Huang, J. S., Kassin, S. A., Koo, D. C., Lotz, J. M., Martin, D. C., Newman, J. A., Noeske, K. G., Papovich, C., , Phillips, A. C., et al. (2007). Star Formation in AEGIS Field Galaxies since z = 1.1: The Dominance of Gradually Declining Star Formation, and the Main Sequence of Star-forming Galaxies. The Astrophysical Journal, 660(1), L43-L46. doi:10.1086/517926
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  We analyze star formation (SF) as a function of stellar mass (M☉) and redshift z in the All-Wavelength Extended Groth Strip International Survey. For 2905 field galaxies, complete to 10^10(10^10.8 )M at z < 0.7(1), with Keck spectroscopic redshifts out to z = 1.1, we compile SF rates (SFRs) from emission lines, GALEX, and Spitzer MIPS 24 µm photometry, optical-NIR M* measurements, and HST morphologies. Galaxies with reliable signs of SF form a distinct “main sequence” (MS), with a limited range of SFRs at a given M* and z (1 σ ≾ ±0.3 dex), and log (SFR) approximately proportional to log M*. The range of log (SFR) remains constant to z > 1, while the MS as a whole moves to higher SFR as z increases. The range of the SFR along the MS constrains the amplitude of episodic variations of SF and the effect of mergers on the SFR. Typical galaxies spend ∼67%(95%) of their lifetime since z = 1 within a factor of ≾2(4) of their average SFR at a given M* and z. The dominant mode of the evolution of SF since z ∼ 1 is apparently a gradual decline of the average SFR in most individual galaxies, not a decreasing frequency of starburst episodes, or a decreasing factor by which SFRs are enhanced in starbursts. LIRGs at z ∼ 1 seem to mostly reflect the high SFR typical for massive galaxies at that epoch. The smooth MS may reflect that the same set of few physical processes governs SF prior to additional quenching processes. A gradual process like gas exhaustion may play a dominant role.
• Barmby, P., Coil, A. L., Cooper, M. C., Faber, S. M., Georgakakis, A., Gwyn, S. D., Koekemoer, A. M., Koo, D. C., Laird, E. S., Lin, L., Lotz, J. M., Nandra, K., Noeske, K. G., Park, S. Q., Pierce, C. M., Primack, J. R., Weiner, B. J., Willmer, C. N., & Willner, S. P. (2007). AEGIS: Host Galaxy Morphologies of X-Ray-selected and Infrared-selected Active Galactic Nuclei at 0.2 ≤ z < 1.2. The Astrophysical Journal, 660(1), L19-L22. doi:10.1086/517922
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  We visually and quantitatively determine the host galaxy morphologies of 94 intermediate-redshift (0.2 ≤ z < 1.2) active galactic nuclei (AGNs), selected using Chandra X-ray data and Spitzer mid-infrared data in the Extended Groth Strip. Using recently developed morphology measures, the second-order moment of the brightest 20% of a galaxy's flux (M20) and the Gini coefficient, we find that X-ray-selected AGNs mostly reside in E/S0/Sa galaxies (53%), while IR-selected AGNs show no clear preference for host morphology. X-ray-selected AGN hosts are members of close pairs more often than the field population by a factor of 3.3 ± 1.4, but most of these pair members appear to be undisturbed early-type galaxies and do not tend to show direct evidence of gravitational perturbations or interactions. Thus, the activation mechanism for AGN activity remains unknown, even for pair members.
• Bundy, K., Coil, A. L., Conselice, C. J., Cooper, M. C., Davis, M., Faber, S. M., Gerke, B. F., Guhathakurta, P., Koo, D. C., Newman, J. A., Noeske, K. G., Weiner, B. J., Willmer, C. N., & Yan, R. (2007). The DEEP2 Galaxy Redshift Survey: the role of galaxy environment in the cosmic star formation history. Monthly Notices of the Royal Astronomical Society, 383(3), 1058-1078. doi:10.1111/j.1365-2966.2007.12613.x
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  Using galaxy samples drawn from the Sloan Digital Sky Survey and the DEEP2 Galaxy Redshift Survey, we study the relationship between star formation and environment at z ∼ 0.1 and 1. We estimate the total star formation rate (SFR) and specific star formation rate (sSFR) for each galaxy according to the measured [O II] λ 3727 A nebular line luminosity, corrected using empirical calibrations to match more robust SFR indicators. Echoing previous results, we find that in the local Universe star formation depends on environment such that galaxies in regions of higher overdensity, on average, have lower SFRs and longer star formation time-scales than their counterparts in lower density regions. At z ∼ 1, we show that the relationship between sSFR and environment mirrors that found locally. However, we discover that the relationship between total SFR and overdensity at z ∼ 1 is inverted relative to the local relation. This observed evolution in the SFR-density relation is driven, in part, by a population of bright, blue galaxies in dense environments at z ∼ 1. This population, which lacks a counterpart at z ∼ 0, is thought to evolve into members of the red sequence from z ∼ 1 to ∼ 0. Finally, we conclude that environment does not play a dominant role in the cosmic star formation history at z < 1: the dependence of the mean galaxy SFR on local galaxy density at constant redshift is small compared to the decline in the global SFR space density over the last 7 Gyr.
• Bundy, K., Coil, A. L., Conselice, C. J., Cooper, M. C., Eisenhardt, P. R., Guhathakurta, P., Huang, J. S., Ivison, R. J., Kassin, S. A., Kirby, E. N., Konidaris, N. P., Lotz, J. M., Newman, J. A., Noeske, K. G., Rich, R. M., Small, T. A., Willmer, C. N., & Willner, S. P. (2007). AEGIS: Galaxy Spectral Energy Distributions from the X-Ray to Radio. The Astrophysical Journal, 660(1), L7-L10. doi:10.1086/517929
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  The All-Wavelength Extended Groth Strip International Survey (AEGIS) team presents broadband spectral energy distributions (SEDs), from X-ray to radio wavelengths, for 71 galaxies spanning the redshift range 0.55-1.16 ( ~ 0.7). Galaxies with secure redshifts are selected from a small (22 arcmin^2) subsection of the Keck/DEIMOS Galaxy Redshift Survey in the Extended Groth Strip field that has also been targeted for deep panchromatic imaging by ultraviolet (120-250 nm), optical (360-900 nm), optical/near-infrared (440-1600 nm), near-infrared (1200-2200 nm), mid/far-infrared (3.6-70 μm), and radio (6-20 cm). A typical galaxy in our sample is M_B = -19.82. The ultraviolet to mid-infrared portion of their SEDs are found to be bracketed by two stellar-only model SEDs: (1) an early burst followed by passive evolution and (2) a constant star formation rate since early times. This suggests that few of these galaxies are undergoing major starbursts. Approximately half the galaxies show a mid- to far-infrared excess relative to the model SEDs, consistent with thermal emission from interstellar dust. Two objects have power-law SEDs, indicating that they are dominated by active galactic nuclei; both are detected in X-rays. SEDs, from the ultraviolet to the infrared, follow expected trends: redder SEDs are associated with red U - B, early-type morphology, and low [O II] emission, and vice versa for blue SEDs.
• Bundy, K., Coil, A. L., Conselice, C. J., Eisenhardt, P., Ellis, R. S., Georgakakis, A., Huang, J. S., Lotz, J. M., Nandra, K., Newman, J. A., Papovich, C., Trujillo, I., Weiner, B. J., & Willmer, C. N. (2007). The properties and evolution of a K-band selected sample of massive galaxies at z∼ 0.4–2 in the Palomar/DEEP2 survey. Monthly Notices of the Royal Astronomical Society, 381(3), 962-986. doi:10.1111/j.1365-2966.2007.12316.x
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  We present the results of a study on the properties and evolution of massive (M* > 10 11 M⊙) galaxies at z ∼ 0.4-2 utilizing Keck spectroscopy, near-infrared Palomar imaging, and Hubble, Chandra and Spitzer data covering fields targeted by the DEEP2 galaxy spectroscopic survey. Our sample is K-band selected and stellar mass limited, based on wide-area near-infrared imaging from the Palomar Observatory Wide-Field Infrared Survey, which covers 1.53 deg 2 to a 5σ depth of K s,vega ∼ 20.5. Our primary goal is to obtain a broad census of massive galaxies through measuring how their number and mass densities, morphology, as well as their star formation and active galactic nucleus content evolve from z ∼ 0.4-2. Our major findings include: (i) statistically the mass and number densities of M* > 10 11 M⊙ galaxies show little evolution between z = 0 and 1 and from z ∼ 0 to 2 for M* > 10 11.5 M⊙ galaxies. We however find significant evolution within 1 10 11 M⊙ selected galaxies show a nearly constant elliptical fraction of ∼70-90 per cent at all redshifts. The remaining objects tend to be peculiars possibly undergoing mergers at z > 0.8, while spirals dominate the remainder at lower redshifts. A significant fraction (∼25 per cent) of these early-types contain minor structural anomalies. (iii) We find that only a fraction (∼60 per cent) of massive galaxies with M* > 10 11 M⊙ are on the red sequence at z ∼ 1.4, while nearly 100 per cent evolve on to it by z ∼ 0.4. (iv) By utilizing Spitzer MIPS imaging and [O II] line fluxes we argue that M* > 10 11.5 M⊙ galaxies have a steeply declining star formation rate (SFR) density ∼ (1 + z) 6 . By examining the contribution of star formation to the evolution of the mass function, as well as the merger history through the CAS parameters, we determine that M* > 10 11 M⊙ galaxies undergo on average 0.9 +0.7 -0.5 major mergers at 0.4 10 11 M⊙ galaxies are X-ray emitters. Roughly half of these are morphologically distorted ellipticals or peculiars. Finally, we compare our mass growth with semi-analytical models from the Millennium Simulation, finding relative good agreement at z 10 1.5 M⊙ galaxies are underpredicted by a factor of > 100.
• Bundy, K., Cooper, M. C., Croton, D. J., Diemand, J., Faber, S. M., Harker, J. J., Kassin, S. A., Konidaris, N. P., Koo, D. C., Lotz, J. M., Metevier, A. J., Noeske, K. G., Phillips, A. C., Weiner, B. J., & Willmer, C. N. (2007). The stellar mass Tully-Fisher relation to z = 1.2 from AEGIS. The Astrophysical Journal, 660(1), L35-L38. doi:10.1086/517932
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  We combine newly measured rotation velocities, velocity dispersions, and stellar masses to construct stellar mass Tully-Fisher relations (M*TFRs) for 544 galaxies with strong emission lines at 0.1 < z < 1.2 from the All-Wavelength Extended Groth Strip International Survey (AEGIS) and the Deep Extragalactic Evolutionary Probe 2 (DEEP2) survey. The conventional M*TFR using only rotation velocity (Vrot) shows large scatter (~1.5 dex in velocity). The scatter and residuals are correlated with morphology in the sense that disturbed, compact, and major merger galaxies have lower velocities for their masses. We construct an M*TFR using the kinematic estimator S0.5, which is defined as 1/2 and accounts for disordered or noncircular motions through the gas velocity dispersion (σg). The new M*TFR, termed S0.5/M*TFR, is remarkably tight over 0.1 < z < 1.2, with no detectable evolution of its intercept or slope with redshift. The average best-fit relation has 0.47 dex scatter in stellar mass, corresponding to ~1.2 "magnitudes," assuming a constant mass-to-light ratio. Interestingly, the S0.5/M*TFR is consistent with the absorption-line-based stellar mass Faber-Jackson relation for nearby elliptical galaxies in terms of slope and intercept, which might suggest a physical connection between the two relations.
• Chiueh, T., Coil, A. L., Conselice, C. J., Cooper, M. C., Floc'h, E. L., Guhathakurta, P., Huang, J. S., Koo, D. C., Lin, L., Lotz, J. M., Noeske, K. G., Phillips, A. C., Smith, H. A., Weiner, B. J., Willmer, C. N., & Willner, S. P. (2007). AEGIS: Enhancement of Dust-enshrouded Star Formation in Close Galaxy Pairs and Merging Galaxies up to z ~ 1*. The Astrophysical Journal, 660(1), L51-L54. doi:10.1086/517919
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  Using data from the DEEP2 Galaxy Redshift Survey and HST/ACS imaging in the Extended Groth Strip, we select nearly 100 interacting galaxy systems, including kinematic close pairs and morphologically identified merging galaxies. Spitzer MIPS 24 μm fluxes of these systems reflect the current dusty star formation activity, and at a fixed stellar mass (M*) the median infrared luminosity (LIR) among merging galaxies and close pairs of blue galaxies is twice (1.9 ± 0.4) that of control pairs drawn from isolated blue galaxies. Enhancement declines with galaxy separation, being strongest in close pairs and mergers and weaker in wide pairs compared to the control sample. At ~ 0.9, 7.1% ± 4.3% of massive interacting galaxies (M* > 2 × 1010 M☉) are found to be ULIRGs, compared to 2.6% ± 0.7% in the control sample. The large spread of LIR/M* among interacting galaxies suggests that this enhancement may depend on the merger stage as well as other as yet unidentified factors (e.g., galaxy structure, mass ratio, orbital characteristics, presence of AGN or bar). The contribution of interacting systems to the total IR luminosity density is moderate (36%).
• Coil, A. L., Cooper, M. C., Croton, D. J., Davis, M., Faber, S. M., Gerke, B. F., Guhathakurta, P., Koo, D. C., Newman, J. A., Weiner, B. J., Willmer, C. N., & Yan, R. (2007). The DEEP2 galaxy redshift survey: the evolution of the blue fraction in groups and the field. Monthly Notices of the Royal Astronomical Society, 376(4), 1425-1444. doi:10.1111/j.1365-2966.2007.11374.x
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  We explore the behaviour of the blue galaxy fraction over the redshift range 0.75 z 1.3 in the DEEP2 Survey, both for field galaxies and for galaxies in groups. The primary aim is to determine the role that groups play in driving the evolution of galaxy colour at high z .I n pursuing this aim, it is essential to define a galaxy sample that does not suffer from redshiftdependent selection effects in colour‐magnitude space. We develop four such samples for this study: at all redshifts considered, each one is complete in colour‐magnitude space, and the selection also accounts for evolution in the galaxy luminosity function. These samples will also be useful for future evolutionary studies in DEEP2. The colour segregation observed between local group and field samples is already in place at z ∼ 1: DEEP2 groups have a significantly lower blue fraction than the field. At fixed z, there is also a correlation between blue fraction and galaxy magnitude, such that brighter galaxies are more likely to be red, both in groups and in the field. In addition, there is a negative correlation between blue fraction and group richness. In terms of evolution, the blue fraction in groups and the field remains roughly constant from z = 0.75 to 1, but beyond this redshift the blue fraction in groups rises rapidly with z, and the group and field blue fractions become indistinguishable at z ∼ 1.3. Careful tests indicate that this effect does not arise from known systematic or selection effects. To further ensure the robustness of this result, we build on previous mock DEEP2 catalogues to develop mock catalogues that reproduce the colour‐overdensity relation observed in DEEP2 and use these to test our methods. The convergence between the group and field blue fractions at z ∼ 1.3 implies that DEEP2 galaxy groups only became efficient at quenching star formation at z ∼ 2; this result is broadly consistent with other recent observations and with current models of galaxy evolution and hierarchical structure growth.
• Coil, A. L., Cooper, M. C., Davis, M., Fassnacht, C. D., Guhathakurta, P., Hopkins, A. M., Koekemoer, A. M., Konidaris, N. P., Lotz, J. M., Marshall, P., Moustakas, L. A., Newman, J. A., & Willmer, C. N. (2007). A Strong-Lens Survey in AEGIS: The Influence of Large-Scale Structure. The Astrophysical Journal, 660(1), L31-L34. doi:10.1086/517930
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  We report on a visual search for galaxy-scale strong gravitational lenses over 650 arcmin2 of HST ACS (V606 and I814) imaging in the DEEP2 Extended Groth Strip. This field has Keck DEIMOS spectroscopy of ~14,000 galaxies (~75% complete to RAB < 24.1). We identify three strong galaxy-galaxy lenses: HST J141735+522646 is a previously known four-image lens (the "Cross"; zl = 0.8106, zs = 3.40); HST J141820+523611 (the "Dewdrop"; zl = 0.5798, zs = 0.9818) features two pairs of arcs; and HST J141833+524352 (the "Anchor"; zl = 0.4625, no zs) has one pair of arcs. Based on a normalized local density (1 + δ3), lenses are found to be in both under- and overdense local environments. All three lenses are fit well by singular isothermal ellipsoid models including external shear, with χ ~ 1. The model shears are ~10%. Approximating all line-of-sight galaxies as singular isothermal sphere halos truncated at 200 h-1 kpc, with masses estimated through the Faber-Jackson relation, infers shears of ~2%, much smaller than those required by the models. Therefore, the corresponding convergence estimates must also be suspect. If more realistic treatment of galaxies (and the large-scale structure that they are embedded in) were to match the inferred shears to the model shears, then the true convergence could be measured and the mass-sheet degeneracy broken.
• Hinz, J. L., Blaylock, M., Engelbracht, C. W., Misselt, K., Pickering, T. E., Rieke, M. J., Rieke, G. H., & Willmer, C. N. (2007). Spitzer observations of low-luminosity isolated and low surface brightness galaxies. The Astrophysical Journal, 663(2), 895-907. doi:10.1086/518817
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  We examine the infrared properties of five low surface brightness galaxies (LSBGs) and compare them with related but higher surface brightness galaxies, using Spitzer Space Telescope images and spectra. All the LSBGs are detected in the 3.6 and 4.5 μm bands, representing the stellar population. All but one are detected at 5.8 and 8.0 μm, revealing emission from hot dust and aromatic molecules, although many are faint or pointlike at these wavelengths. Detections of LSBGs at the far-infrared wavelengths of 24, 70, and 160 μm are varied in morphology and brightness, with only two detections at 160 μm, resulting in highly varied spectral energy distributions. Consistent with previous expectations for these galaxies, we find that detectable dust components exist for only some LSBGs, with the strength of dust emission dependent on the existence of bright star-forming regions. However, the far-infrared emission may be relatively weak compared with normal star-forming galaxies.
• Huang, J. S., Ashby, M. L., Barmby, P., Brodwin, M., Brown, M. J., Caldwell, N., Cool, R. J., Eisenhardt, P., Fazio, G. G., Kochanek, C. S., Lu, N., Pahre, M. A., Rigopoulou, D., Rosenberg, J. L., Smith, H. A., Wang, Z., Willmer, C. N., Willner, S. P., Eisenstein, D. J., , Floc'h, E. L., et al. (2007). The Local Galaxy 8 μm Luminosity Function. The Astrophysical Journal, 664(2), 840-849. doi:10.1086/519241
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  A Spitzer Space Telescope survey in the NOAO Deep Wide Field in Bootes provides a complete, 8 μm-selected sample of galaxies to a limiting (Vega) magnitude of 13.5. In the 6.88 deg2 field sampled, 79% of the 4867 galaxies have spectroscopic redshifts, allowing an accurate determination of the local (z < 0.3) galaxy luminosity function. Stellar and dust emission can be separated on the basis of observed galaxy colors. Dust emission (mostly PAH) accounts for 80% of the 8 μm luminosity, stellar photospheres account for 19%, and AGN emission accounts for roughly 1%. A subsample of the 8 μm-selected galaxies have blue, early-type colors, but even most of these have significant PAH emission. The luminosity functions for the total 8 μm luminosity and for the dust emission alone are both well fit by Schechter functions. For the 8 μm luminosity function, the characteristic luminosity is νL(8.0 μm) = 1.8 × 1010 L☉, while for the dust emission alone it is 1.6 × 1010 L☉. The average 8 μm luminosity density at z < 0.3 is 3.1 × 107 L☉ Mpc-3, and the average luminosity density from dust alone is 2.5 × 107 L☉ Mpc-3. This luminosity arises predominantly from galaxies with 8 μm luminosities (νLν) between 2 × 109 and 2 × 1010 L☉, i.e., normal galaxies, not luminous or ultraluminous infrared galaxies (LIRGs/ULIRGs).
• Huang, J. S., Rigopoulou, D., Papovich, C., Ashby, M. L., Willner, S. P., Ivison, R., Laird, E. S., Webb, T., Wilson, G., Barmby, P., Chapman, S., Conselice, C., McLeod, B., Shu, C. G., Smith, H. A., Le Floc'h, E., Egami, E., Willmer, C. A., & Fazio, G. G. (2007). AEGIS: Infrared spectroscopy of an infrared-luminous lyman break galaxy at z = 3.01. Astrophysical Journal, 660(Issue 1). doi:10.1086/508567
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  We report the detection of rest-frame 6.2 and 7.7 μm emission features arising from polycyclic aromatic hydrocarbons (PAHs) in the Spitzer IRS spectrum of an infrared-luminous Lyman break galaxy at z = 3.01. This is currently the highest redshift galaxy where these PAH emission features have been detected. The total IR luminosity inferred from the MIPS 24 μm and radio flux density is 2 × 1013 L⊙, which qualifies this object as a so-called hyperluminous infrared galaxy (HyLIRG). However, unlike local HyLIRGs, which are generally associated with QSO/AGNs and have weak or absent PAH emission features, this HyLIRG has very strong 6.2 and 7.7 μm PAH emission. We argue that intense star formation dominates the IR emission of this source, although we cannot rule out the presence of a deeply obscured AGN. This LBG appears to be a distorted system in the HST ACS F606W and F814W images, possibly indicating that a significant merger or interaction is driving the large IR luminosity. © 2007. The American Astronomical Society. All rights reserved.
• Nandra, K., Georgakakis, A., Willmer, C. N., Cooper, M. C., Croton, D. J., Davis, M., Faber, S. M., Koo, D. C., Laird, E. S., & Newman, J. A. (2007). AEGIS: the color-magnitude relation for X-ray-selected active galactic nuclei. The Astrophysical Journal, 660(1), L11-L14. doi:10.1086/517918
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  We discuss the relationship between rest-frame color and optical luminosity for X-ray sources in the range 0.6 < z < 1.4 selected from the Chandra survey of the Extended Groth Strip. These objects are almost exclusively active galactic nuclei (AGNs). While there are a few luminous QSOs, most are relatively weak or obscured AGNs whose optical colors should be dominated by host galaxy light. The vast majority of AGN hosts at z ~ 1 are luminous and red, with very few objects fainter than MB = -20.5 or bluer than U - B = 0.6. This places the AGNs in a distinct region of color-magnitude space, on the red sequence or at the top of the blue cloud, with many in between these two modes in galaxy color. A key stage in the evolution of massive galaxies is when star formation is quenched, resulting in a migration from the blue cloud to the red sequence. Our results are consistent with scenarios in which AGNs either cause or maintain this quenching. The large number of red-sequence AGNs implies that strong, ongoing star formation is not a necessary ingredient for AGN activity, as black hole accretion appears often to persist after star formation has been terminated.
• Rich, R. M., Ashby, M. L., Barmby, P., Biggs, A. D., Bundy, K., Chapman, S. C., Coil, A. L., Conselice, C. J., Cooper, M. C., Croton, D. J., Davis, M., Eisenhardt, P. R., Ellis, R. S., Faber, S. M., Fang, T., Fazio, G. G., Floc'h, E. L., Georgakakis, A., Gerke, B. F., , Goss, W. M., et al. (2007). The All-Wavelength Extended Groth Strip International Survey(AEGIS) Data Sets. The Astrophysical Journal, 660(1), L1-L6. doi:10.1086/517931
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  In this the first of a series of Letters, we present a panchromatic data set in the Extended Groth Strip region of the sky. Our survey, the All-Wavelength Extended Groth Strip International Survey (AEGIS), aims to study the physical properties and evolutionary processes of galaxies at z ~ 1. It includes the following deep, wide-field imaging data sets: Chandra/ACIS X-ray, GALEX ultraviolet, CFHT/MegaCam Legacy Survey optical, CFHT/CFH12K optical, Hubble Space Telescope/ACS optical and NICMOS near-infrared, Palomar/WIRC near-infrared, Spitzer/IRAC mid-infrared, Spitzer/MIPS far-infrared, and VLA radio continuum. In addition, this region of the sky has been targeted for extensive spectroscopy using the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II 10 m telescope. Our survey is compared to other large multiwavelength surveys in terms of depth and sky coverage.
• Willmer, C. N., Coil, A. L., Conroy, C., Cooper, M. C., Davis, M., Faber, S. M., Finkbeiner, D. P., Gebhardt, K., Gerke, B. F., Groth, E. J., Guhathakurta, P., Harker, J., Im, M., Kaiser, N., Kassin, S. A., Kassin, S. A., Kleinheinrich, M., Konidaris, N. P., Koo, D. C., , Kron, R. G., et al. (2007). Galaxy luminosity functions to z∼ 1 from DEEP2 and COMBO-17: Implications for red galaxy formation. The Astrophysical Journal, 665(1), 265-294. doi:10.1086/519294
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  The DEEP2 and COMBO-17 surveys are compared to study luminosity functions of red and blue galaxies to z ~ 1. The two surveys have different methods and sensitivities, but nevertheless results agree. After z ~ 1, M has dimmed by 1.2-1.3 mag for all colors of galaxies, * for blue galaxies has hardly changed, and * for red galaxies has at least doubled (our formal value is ~0.5 dex). Luminosity density jB has fallen by 0.6 dex for blue galaxies but has remained nearly constant for red galaxies. These results imply that the number and total stellar mass of blue galaxies have been substantially constant since z ~ 1, whereas those of red galaxies (near L*) have been significantly rising. To explain the new red galaxies, a ``mixed'' scenario is proposed in which star formation in blue cloud galaxies is quenched, causing them to migrate to the red sequence, where they merge further in a small number of stellar mergers. This mixed scenario matches the local boxy-disky transition for nearby ellipticals, as well as red sequence stellar population scaling laws such as the color-magnitude and Mg-? relations (which are explained as fossil relics from blue progenitors). Blue galaxies enter the red sequence via different quenching modes, each of which peaks at a different characteristic mass and time. The red sequence therefore likely builds up in different ways at different times and masses, and the concept of a single process that is ``downsizing'' (or upsizing) probably does not apply. Our claim in this paper of a rise in the number of red galaxies applies to galaxies near L*. Accurate counts of brighter galaxies on the steep part of the Schechter function require more accurate photometry than is currently available.
• Willmer, C. N., Coil, A. L., Cooper, M. C., Croton, D. J., Davis, M., Faber, S. M., Gerke, B. F., Guhathakurta, P., Koo, D. C., Newman, J. A., Weiner, B. J., & Yan, R. (2007). The DEEP2 galaxy redshift survey: evolution of the colour–density relation at 0.4 < z < 1.35. Monthly Notices of the Royal Astronomical Society, 376(4), 1445-1459. doi:10.1111/j.1365-2966.2007.11534.x
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  Using a sample of 19464 galaxies drawn from the DEEP2 Galaxy Redshift Survey, we study the relationship between galaxy colour and environment at 0.4 1, being larger in regions of greater galaxy density. At all epochs probed, we also find a small population of red, morphologically early-type galaxies residing in regions of low measured overdensity. The observed correlations between the red fraction and local overdensity are highly significant, with the trend at z > 1 detected at a greater than 5σ level. Over the entire redshift regime studied, we find that the colour-density relation evolves continuously, with red galaxies more strongly favouring overdense regions at low z relative to their red-sequence counterparts at high redshift. At z ≥ 1.3, the red fraction only weakly correlates with overdensity, implying that any colour dependence to the clustering of ∼L* galaxies at that epoch must be small. Our findings add weight to existing evidence that the build-up of galaxies on the red sequence has occurred preferentially in overdense environments (i.e. galaxy groups) at z≤ 1.5. Furthermore, we identify the epoch (z ∼ 2) at which typical ∼L* galaxies began quenching and moved on to the red sequence in significant number. The strength of the observed evolutionary trends at 0 < z < 1.35 suggests that the correlations observed locally, such as the morphology-density and colour-density relations, are the result of environment-driven mechanisms (i.e. 'nurture') and do not appear to have been imprinted (by 'nature') upon the galaxy population during their epoch of formation.
• Willmer, C. N., Smith, J. D., Elbaz, D., Ashby, M. L., Bai, L., Barmby, P., Blaylock, M., Bundy, K., Chapman, S., Coil, A. L., Conselice, C. J., Dole, H., Egami, E., Elbaz, D., Floc'h, E. L., Huang, J. S., Ivison, R., Konidaris, N. P., Koo, D. C., , Laird, E. S., et al. (2007). Far-Infrared Characterization of an Ultraluminous Starburst Associated with a Massively Accreting Black Hole at z = 1.15. The Astrophysical Journal, 660(1), L65-L68. doi:10.1086/517916
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  As part of the All-Wavelength Extended Groth Strip International Survey (AEGIS), we describe the panchromatic characterization of an X-ray–luminous active galactic nucleus (AGN) in a merging galaxy at z = 1.15. This object is detected at infrared (8, 24, 70, and 160 μm), submillimeter (850 μm), and radio wavelengths, from which we derive a bolometric luminosity Lbol ∼ 9 x 10^12 L☉. We find that the AGN clearly dominates the hot dust emission below 40 μm but its total energetic power inferred from the hard X-rays is substantially less than the bolometric output of the system. About 50% of the infrared luminosity is indeed produced by a cold dust component that probably originates from enshrouded star formation in the host galaxy. In the context of a coeval growth of stellar bulges and massive black holes, this source might represent a “transition” object, sharing properties with both quasars and luminous starbursts. Study of such composite galaxies will help address how the star formation and disk-accretion phenomena may have regulated each other at high redshift and how this coordination may have participated in the buildup of the relationship observed locally between the masses of black holes and stellar spheroids.
• Bundy, K., Coil, A. L., Conselice, C. J., Cooper, M. C., Eisenhardt, P. R., Ellis, R. S., Noeske, K. G., Taylor, J. E., Weiner, B. J., & Willmer, C. N. (2006). The mass assembly history of field galaxies: detection of an evolving mass limit for star forming galaxies. The Astrophysical Journal, 651(1), 120-141. doi:10.1086/507456
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  We characterize the mass-dependent evolution of more than 8000 galaxies using spectroscopic redshifts from the DEEP2 Galaxy Redshift Survey in the range 0.4 < z < 1.4 and stellar masses calculated from K-band photometry obtained at Palomar Observatory. This sample spans more than 1.5 deg^2 in four independent fields. Using rest-frame U - B color and [O II] equivalent widths, we distinguish star-forming from passive populations in order to explore the nature of "downsizing"—a pattern in which the sites of active star formation shift from high-mass galaxies at early times to lower mass systems at later epochs. We identify a mass limit, M_Q, above which star formation appears to be quenched and show that the physical mechanisms responsible for downsizing can thus be empirically quantified by charting the evolution in this threshold mass. We find that M_Q decreases with time by a factor of ~3 across our redshift range according to M_Q α (1 + z)^(3.5). To further constrain possible quenching mechanisms, we investigate how downsizing depends on local galaxy environment using the projected third-nearest-neighbor statistic D_(p,3). For the majority of galaxies near the median density, there is no significant correlation between downsizing and environment. However, a trend is observed in the comparison between environments that are more than 3 times overdense or underdense relative to the median. Here, downsizing appears accelerated in overdense regions that host higher numbers of massive, early-type galaxies as compared to the underdense regions. Our results significantly constrain recent suggestions for the origin of downsizing and indicate that the process for quenching star formation must, primarily, be internally driven
• Coil, A. L., Connolly, A. J., Conroy, C., Cooper, M. C., Davis, M., Faber, S. M., Finkbeiner, D. P., Gerke, B. F., Guhathakurta, P., Harker, J., Kaiser, N., Kassin, S. A., Kassin, S. A., Konidaris, N. P., Koo, D. C., Lin, L., Luppino, G. A., Madgwick, D. S., Newman, J. A., , Noeske, K. G., et al. (2006). The Deep Evolutionary Exploratory Probe 2 Galaxy Redshift Survey: The Galaxy Luminosity Function to z ~ 1*. The Astrophysical Journal, 647(2), 853-873. doi:10.1086/505455
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  The evolution of the B-band galaxy luminosity function is measured using a sample of more than 11,000 galaxies with spectroscopic redshifts from the DEEP2 Redshift Survey. The rest-frame MB versus U - B color-magnitude diagram of DEEP2 galaxies shows that the color-magnitude bimodality seen in galaxies locally is still present at redshifts z > 1. Dividing the sample at the trough of this color bimodality into predominantly red and blue galaxies, we find that the luminosity function of each galaxy color type evolves differently. Blue counts tend to shift to brighter magnitudes at constant number density, while the red counts remain largely constant at a fixed absolute magnitude. Using Schechter functions with fixed faint-end slopes we find that M for blue galaxies brightens by ~1.3 ? 0.14 mag per unit redshift, with no significant evolution in number density. For red galaxies M brightens somewhat less with redshift, while the formal value of * declines. When the population of blue galaxies is subdivided into two halves using the rest-frame color as the criterion, the measured evolution of both blue subpopulations is very similar.
• Coil, A. L., Cooper, M. C., Croton, D. J., Davis, M., Faber, S. M., Finkbeiner, D. P., Gerke, B. F., Guhathakurta, P., Koo, D. C., Madgwick, D. S., Newman, J. A., Weiner, B. J., & Willmer, C. N. (2006). The DEEP2 Galaxy Redshift Survey: the relationship between galaxy properties and environment at z∼ 1. Monthly Notices of the Royal Astronomical Society, 370(1), 198-212. doi:10.1111/j.1365-2966.2006.10485.x
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  We study the mean environment of galaxies in the DEEP2 Galaxy Redshift Survey as a function of rest-frame color, luminosity, and [OII] 3727u equivalent width. The local galaxy overdensity for > 14,000 galaxies at 0.75 < z < 1.35 is estimated using the projected 3 rd -nearest-neighbor surface density. Of the galaxy properties studied, mean environment is found to depend most strongly on galaxy color; all major features of the correlation between mean overdensity and rest-frame color observed in the local universe were already in place at z ∼ 1. In contrast to local results, we find a substantial slope in the mean dependence of environment on luminosity for blue, star-forming galaxies at z ∼ 1, with brighter blue galaxies being found on average in regions of greater overdensity. We discuss the roles of galaxy clusters and groups in establishing the observed correlations between environment and galaxy properties at high redshift, and we also explore the evidence for a “downsizing of quenching” from z ∼ 1 to z ∼ 0. Our results add weight to existing evidence that the mechanism(s) that result in star-formation quenching are efficient in group environments as well as clusters. This work is the first of its kind at high redshift and represents the first in a series of papers addressing the role of environment in galaxy formation at 0 < z < 1. Subject headings: galaxies:high-redshift, galaxies:evolution, galaxies:statistics, galaxies:fundamental parameters, large-scale structure of universe
• Coil, A. L., Cooper, M. C., Davis, M., Faber, S. M., Koo, D. C., Newman, J. A., & Willmer, C. N. (2006). The DEEP2 Galaxy Redshift Survey: Clustering of Galaxies as a Function of Luminosity at z = 1. The Astrophysical Journal, 644(2), 671-677. doi:10.1086/503601
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  We measure the clustering of DEEP2 galaxies at z = 1 as a function of luminosity on scales 0.1-20 h-1 Mpc. Drawing from a parent catalog of 25,000 galaxies at 0.7 L*, have a steeper slope. The clustering scale length, r0, varies from 3.69 ± 0.14 for the faintest sample to 4.43 ± 0.14 for the brightest sample. The relative bias of galaxies as a function of L/L* is steeper than the relation found locally for SDSS galaxies by Zehavi et al. in 2005 over the luminosity range that we sample. The absolute bias of galaxies at z ~ 1 is scale dependent on scales rp < 1 h-1 Mpc, and rises most significantly on small scales for the brightest samples. For a concordance cosmology, the large-scale bias varies from 1.26 ± 0.04 to 1.54 ± 0.05 as a function of luminosity and implies that DEEP2 galaxies reside in dark matter halos with a minimum mass of ~ × 1012 h-1 M☉.
• Faber, S. M., Harker, J., Kassin, S. A., Koo, D. C., Melbourne, J., Metevier, A. J., Phillips, A. C., Vogt, N. P., Weiner, B. J., & Willmer, C. N. (2006). A Survey of Galaxy Kinematics to z ~ 1 in the TKRS/GOODS-N Field. I. Rotation and Dispersion Properties. The Astrophysical Journal, 653(2), 1027-1048. doi:10.1086/508921
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  We present kinematic measurements of a large sample of galaxies from the Team Keck Redshift Survey in the GOODS-N field. We measure line-of-sight velocity dispersions from integrated emission for 1089 galaxies with median redshift 0.637 and spatially resolved kinematics for a subsample of 380 galaxies. This is the largest sample of galaxies to z ~ 1 with kinematics to date and allows us to measure kinematic properties without morphological preselection. Emission-line widths provide a dynamical measurement for the bulk of blue galaxies. To fit the spatially resolved kinematics, we construct models that fit both line-of-sight rotation amplitude and velocity dispersion. Integrated line width correlates well with a combination of the velocity gradient and dispersion and is a robust measure of galaxy kinematics. The spatial extents of emission and continuum are similar, and there is no evidence that line widths are affected by nuclear or clumpy emission. The measured rotation gradient depends strongly on slit position angle alignment with galaxy major axis, but integrated line width does not. Even for galaxies with well-aligned slits, some have kinematics dominated by dispersion (V/σ < 1) rather than rotation. These are probably objects with disordered velocity fields, not dynamically hot stellar systems. About 35% of the spatially resolved sample are dispersion dominated; galaxies that are both dispersion dominated and bright exist at high redshift but appear rare at low redshift. This kinematic morphology may probe galaxies' evolutionary state. It is linked to photometric morphology in HST ACS images: dispersion-dominated galaxies include a higher fraction of irregulars and chain galaxies, while rotation-dominated galaxies are mostly disks and irregulars. Only one-third of chain/hyphen galaxies are dominated by rotation; high-redshift elongated objects cannot be assumed to be inclined disks.
• Faber, S. M., Harker, J., Kassin, S. A., Koo, D. C., Melbourne, J., Metevier, A. J., Phillips, A. C., Vogt, N. P., Weiner, B. J., & Willmer, C. N. (2006). A Survey of Galaxy Kinematics to z ~ 1 in the TKRS/GOODS-N Field. II. Evolution in the Tully-Fisher Relation. The Astrophysical Journal, 653(2), 1049-1069. doi:10.1086/508922
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  We use kinematic measurements of a large sample of galaxies from the Team Keck Redshift Survey in the GOODS-N field to measure evolution in the optical and near-IR Tully-Fisher (TF) relations to z = 1.2. We construct TF relations with integrated line-of-sight velocity widths of ~1000 galaxies in B and ~670 in J; these relations have large scatter, and we derive a maximum likelihood least-squares method for fitting in the presence of scatter. The B-band TF relations, from z = 0.4 to 1.2, show evolution of ~1.0-1.5 mag internal to our sample without requiring calibration to a local TF relation. There is evolution in both TF intercept and slope, suggesting differential luminosity evolution. In J band, there is evolution in slope but little evolution in overall luminosity. The slope measurements imply that bright, massive blue galaxies fade more strongly than fainter blue galaxies from z ~ 1.2 to now. This conclusion runs counter to some previous measurements and to our naive expectations, but we present a simple set of star formation histories to show that it arises naturally if massive galaxies have shorter timescales of star formation, forming most of their stars before z ~ 1, while less massive galaxies form stars at more slowly declining rates. This model predicts that the higher global star formation rate at z ~ 1 is mostly due to higher star formation rate in massive galaxies. The amount of fading in B constrains star formation timescale more strongly than redshift of formation. TF and color-magnitude relations can provide global constraints on the luminosity evolution and star formation history of blue galaxies.
• Gebhardt, K., Im, M., Iverson, S., Kobulnicky, H. A., Koo, D. C., Laird, E. S., Mattos, W., Phillips, A. C., Sarajedini, V. L., Vogt, N. P., & Willmer, C. N. (2006). The DEEP Groth Strip Survey. VI. Spectroscopic, Variability, and X-Ray Detection of Active Galactic Nuclei. Astrophysical Journal Supplement Series, 166(1), 69-88. doi:10.1086/505909
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  We identify active galactic nuclei (AGNs) in the Groth-Westphal Survey Strip (GSS) using the independent and complementary selection techniques of optical spectroscopy and photometric variability. We discuss the X-ray properties of these AGNs using Chandra/XMM-Newton data for this region. From a sample of 576 galaxies with high-quality spectra we identify 31 galaxies with AGN signatures. Seven of these have broad emission lines (Type 1 AGNs). We also identify 26 galaxies displaying nuclear variability in Hubble Space Telescope Wide Field Planetary Camera 2 (HST WFPC2) images of the GSS separated by ~7 yr. The primary overlap of the two selected AGN samples is the set of broad-line AGNs, of which 80% appear as variable. Only a few narrow-line AGNs approach the variability threshold. The broad-line AGNs have an average redshift of z 1.1, while the other spectroscopic AGNs have redshifts closer to the mean of the general galaxy population (z 0.7). Eighty percent of the identified broad-line AGNs are detected in X-rays, and these are among the most luminous X-ray sources in the GSS. Only one narrow-line AGN is X-ray detected. Of the variable nuclei galaxies within the X-ray survey, 27% are X-ray detected. We find that 1.9% ? 0.6% of GSS galaxies to Vgal = 24 are broad-line AGNs, 1.4% ? 0.5% are narrow-line AGNs, and 4.5% ? 1.4% contain variable nuclei. The fraction of spectroscopically identified BLAGNs and NLAGNs at z ~ 1 reveals a marginally significant increase of 1.3% ? 0.9% when compared to the local population.
• Koo, D. C., Melbourne, J., Noeske, K. G., Papaderos, P., Paz, A. G., Phillips, A. C., & Willmer, C. N. (2006). Luminous compact blue galaxies up to z ~ 1 in the Hubble space telescope ultra deep field. I. Small galaxies or blue centers of massive disks?. The Astrophysical Journal, 640(2), L143-L146. doi:10.1086/503556
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  We analyze 26 luminous compact blue galaxies (LCBGs) in the Hubble Space Telescope ACS Ultra Deep Field (UDF) at z ~ 0.2-1.3, to determine whether these truly are small galaxies or, rather, bright central starbursts within existing or forming large disk galaxies. Surface brightness profiles from UDF images reach fainter than rest-frame 26.5 B mag arcsec-2 even for compact objects at z ~ 1. Most LCBGs show a smaller, brighter component that is likely star-forming, and an extended, roughly exponential component with colors suggesting stellar ages from 100 Myr to a few gigayears. Scale lengths of the extended components are mostly 2 kpc, more than 1.5-2 times smaller than those of nearby large disk galaxies like the Milky Way. Larger, very low surface brightness disks can be excluded down to faint rest-frame surface brightnesses (26 B mag arcsec-2). However, one or two of the LCBGs are large, disklike galaxies that meet LCBG selection criteria because of a bright central nucleus, possibly a forming bulge. These results indicate that 90% of high-z LCBGs are small galaxies that will evolve into small disk galaxies, or low-mass spheroidal or irregular galaxies in the local universe, assuming passive evolution and no significant disk growth. The data do not reveal signs of disk formation around small, H II galaxy-like LCBGs, nor do they suggest a simple inside-out growth scenario for larger LCBGs with a disklike morphology. Irregular blue emission in distant LCBGs is relatively extended, suggesting that nebular emission lines from star-forming regions sample a major fraction of an LCBG's velocity field.
• Schiavon, R. P., Faber, S. M., Konidaris, N., Graves, G., Willmer, C. N., Weiner, B. J., Coil, A. L., Cooper, M. C., Davis, M., Harker, J., Koo, D. C., Newman, J. A., & Yan, R. (2006). The deep2 galaxy redshift survey: Mean ages and metallicies of red field galaxies at z ∼ 0.9 from stacked keck deimos spectr. Astrophysical Journal, 651(Issue 2). doi:10.1086/509074
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  As part of the DEEP2 galaxy redshift survey, we analyze absorption line strengths in stacked Keck DEIMOS spectra of red field galaxies with weak to no emission lines, at redshifts 0.7 ≤ z ≤ 1. Comparison with models of stellar population synthesis shows that red galaxies at z ∼ 0.9 have mean luminosity-weighted ages of the order of only 1 Gyr and at least solar metallicities. These ages cannot be reconciled with a scenario in which all stars evolved passively after forming at very high z. Rather, a significant fraction of stars can be no more than 1 Gyr old, which means that some star formation in the stacked populations continued to at least z ∼ 1.2. Furthermore, a comparison of these distant galaxies with a local SDSS sample, using stellar population synthesis models, shows that the drop in the equivalent width of Hδ from z ∼ 0.9 to 0.1 is less than that predicted by passively evolving models. This admits two interpretations: either each individual galaxy experiences continuing low-level star formation, or the red-sequence galaxy population from z ∼ 0.9 to 0.1 is continually being added to by new galaxies with younger stars. © 2006. The American Astronomical Society. All rights reserved.
• Blandford, R., Brunner, R. J., Connolly, A. J., Faber, S. M., Gebhardt, K., Gronwall, C., Groth, E. J., Guzman, R., Illingworth, G. D., Im, M., Koo, D. C., Kron, R. G., Phillips, A. C., Rhodes, J., Sarajedini, V. L., Simard, L., Szalay, A. S., Vogt, N. P., Weiner, B. J., , Willmer, C. N., et al. (2005). The DEEP Groth Strip Survey. I. The Sample. Astrophysical Journal Supplement Series, 159(1), 41-59. doi:10.1086/430313
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  The Deep Extragalactic Exploratory Probe (DEEP) is a multiphase research program dedicated to the study of the formation and evolution of galaxies and of large-scale structure in the distant universe. This paper describes the first five-year phase, denoted DEEP1. A series of 10 DEEP1 papers will discuss a range of scientific topics (e.g., the study of photometric and spectral properties of a general distant galaxy survey, the evolution observed in galaxy populations of varied morphologies). The observational basis for these studies is the Groth Survey Strip field, a 127 arcmin2 region that has been observed with the Hubble Space Telescope (HST) in both broad I-band and V-band optical filters and with the Low Resolution Imaging Spectrograph on the Keck Telescopes. Catalogs of photometric and structural parameters have been constructed for 11,547 galaxies and stars at magnitudes brighter than 29, and spectroscopy has been conducted for a magnitude-color weighted subsample of 818 objects. We evaluate three independent techniques for constructing an imaging catalog for the field from the HST data and discuss the depth and sampling of the resultant catalogs. The selection of the spectroscopic subsample is discussed, and we describe the multifaceted approach taken to prioritizing objects of interest for a variety of scientific subprograms. A series of Monte Carlo simulations then demonstrates that the spectroscopic subsample can be adequately modeled as a simple function of magnitude and color cuts in the imaging catalog.
• Bouwens, R. J., Crosby, T., Faber, S. M., Gebhardt, K., Harker, J., Im, M., Kauffmann, G., Koo, D. C., Phillips, A. J., Sarajedini, V. L., Simard, L., Vogt, N. P., Weiner, B. J., Willmer, C. N., & Wu, K. L. (2005). The DEEP groth strip survey - VIII. The evolution of luminous field bulges at redshift z ~ 1. Astrophysical Journal Supplement Series, 157(2), 175-217. doi:10.1086/427845
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  We present a candidate sample of luminous bulges (including ellipticals) found within the Groth Strip Survey (GSS), with spectroscopic redshifts of 0.73 1.5. Only small amounts of residual star formation are needed to explain both the absence of bluening of bulges to today and the presence of emission lines seen in the Keck spectra of the very red distant galaxies.
• Coil, A. L., Conroy, C., Cooper, M. C., Davis, M., Faber, S. M., Finkbeiner, D. P., Gerke, B. F., Guhathakurta, P., Kaiser, N., Koo, D. C., Marinoni, C., Newman, J. A., Phillips, A. C., Weiner, B. J., Willmer, C. N., & Yan, R. (2005). The DEEP2 Galaxy Redshift Survey: First results on galaxy groups. The Astrophysical Journal, 625(1), 6-22. doi:10.1086/429579
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  We use the first 25% of the DEEP2 Galaxy Redshift Survey spectroscopic data to identify groups and clusters of galaxies in redshift space. The data set contains 8370 galaxies with confirmed redshifts in the range 0.7 ≤ z ≤ 1.4, over 1 deg2 on the sky. Groups are identified using an algorithm (the Voronoi-Delaunay method) that has been shown to accurately reproduce the statistics of groups in simulated DEEP2-like samples. We optimize this algorithm for the DEEP2 survey by applying it to realistic mock galaxy catalogs and assessing the results using a stringent set of criteria for measuring group-finding success, which we develop and describe in detail here. We find in particular that the group finder can successfully identify ~78% of real groups and that ~79% of the galaxies that are true members of groups can be identified as such. Conversely, we estimate that ~55% of the groups we find can be definitively identified with real groups and that ~46% of the galaxies we place into groups are interloper field galaxies. Most importantly, we find that it is possible to measure the distribution of groups in redshift and velocity dispersion, n(σ, z), to an accuracy limited by cosmic variance, for dispersions greater than 350 km s-1. We anticipate that such measurements will allow strong constraints to be placed on the equation of state of the dark energy in the future. Finally, we present the first DEEP2 group catalog, which assigns 32% of the galaxies to 899 distinct groups with two or more members, 153 of which have velocity dispersions above 350 km s-1. We provide locations, redshifts and properties for this high-dispersion subsample. This catalog represents the largest sample to date of spectroscopically detected groups at z ~ 1.
• Datta, S., Im, M., Koo, D. C., Simard, L., Tran, K. H., & Willmer, C. N. (2005). Colors of Luminous Bulges in Cluster MS 1054–03 and Field Galaxies at Redshifts z ~ 0.83*. The Astrophysical Journal, 634(1), L5-L8. doi:10.1086/498707
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  Using Hubble Space Telescope images, we separate the bulgelike (dubbed "pbulge") and disklike ("pdisk") components of 71 galaxies in the rich cluster MS 1054-03 and of 21 in the field. Our key finding is that luminous pbulges are very red, with rest-frame U-B ~ 0.45, while predicted colors are bluer by 0.20 mag. Moreover, these very red colors appear to be independent of environment, pbulge luminosity, pdisk color, and pbulge fraction. These results challenge any model of hierarchical galaxy formation that predicts the colors of distant (z ~ 0.8) luminous field and cluster bulges will differ. Our findings also disagree with other claims that 30% to 50% of bright bulges and elliptical galaxies at z ~ 1 are very blue (U-B ≤ 0).
• Guhathakurta, P., Hoyos, C., Koo, D. C., Phillips, A. C., & Willmer, C. N. (2005). The DEEP2 Galaxy Redshift Survey: Discovery of Luminous, Metal-poor Star-forming Galaxies at Redshifts z ~ 0.7*. The Astrophysical Journal, 635(1), L21-L24. doi:10.1086/499232
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  We have discovered a sample of 17 metal-poor, yet luminous, star-forming galaxies at redshifts z ~ 0.7. They were selected from the initial phase of the DEEP2 survey of 3900 galaxies and the Team Keck Redshift Survey (TKRS) of 1536 galaxies as those showing the temperature-sensitive [O III] λ4363 auroral line. These rare galaxies have blue luminosities close to L*, high star formation rates of 5-12 M☉ yr-1, and oxygen abundances of 1/3 to 1/10 solar. They thus lie significantly off the luminosity-metallicity relation found previously for field galaxies with strong emission lines at redshifts z ~ 0.7. The prior surveys relied on indirect, empirical calibrations of the R23 diagnostic and the assumption that luminous galaxies are not metal-poor. Our discovery suggests that this assumption is sometimes invalid. As a class, these newly discovered galaxies are (1) more metal-poor than common classes of bright emission-line galaxies at z ~ 0.7 or at the present epoch; (2) comparable in metallicity to z ~ 3 Lyman break galaxies but less luminous; and (3) comparable in metallicity to local metal-poor extreme blue compact galaxies (XBCGs), but more luminous. Together, the three samples suggest that the most luminous, metal-poor, compact galaxies become fainter over time.
• Koo, D. C., Noeske, K. G., Phillips, A. C., Pisano, D. J., & Willmer, C. N. (2005). H I observations of SA 68-6597 : The faintest blue compact dwarf galaxy. The Astrophysical Journal, 630(1), L25-L28. doi:10.1086/491645
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  Blue compact dwarf galaxies (BCDs) are faint (MB ≤ -17 mag), compact (R < 1 kpc), and at least qualitatively very blue galaxies, due to active star formation, and have low metallicities. Found serendipitously as part of a redshift survey of faint galaxies with the Keck Telescope (DEEP), SA 68-6597 is at a distance of 80 Mpc, and is one of the faintest (-12.4 mag), lowest metallicity (~0.05 Z☉) BCDs known. Its Hβ line width of σ = 27 km s-1 and small size, Reff ~ 190 pc, suggest that it is an extremely low mass galaxy. We have used the Arecibo telescope to measure the H I properties of SA 68-6597 in order to better constrain its total mass and its potential for future star formation. SA 68-6597 has a M = (1.4 ± 0.4) × 107 M☉ and an H I FWHM line width of 33. Combining the H I line width with an estimate of the size of the H I disk, we derive a Mdyn 3 × 107 M☉. The values M/LB = 1.0 ± 0.3 M☉/L☉, Mdyn/LB ≥ 2 M☉/L☉, and M/Mdyn 0.47 are typical for BCDs. Combining the measured star formation rate of 0.003 M☉ yr-1 with the H I mass, we derive a gas depletion timescale of 5 ± 2 Gyr. While SA 68-6597 is a fainter, lower mass, higher metallicity counterpart to other BCDs like I Zw 18 and SBS 0335-052, its H I properties suggest that it will not evolve dramatically in the near future. Given the limits on its gaseous and dynamical masses, SA 68-6597 may be able to evolve into a moderately massive dwarf spheroidal galaxy.
• Kron, R. G., Faber, S. M., Forbes, D. A., Gebhardt, K., Gronwall, C., Groth, E. J., Illingworth, G. D., Im, M., Koo, D. C., Kron, R. G., Phillips, A. C., Rhodes, J., Sarajedini, V. L., Simard, L., Szalay, A. S., Takamiya, M., Vogt, N. P., Weiner, B. J., Willmer, C. N., & Wu, K. L. (2005). THE DEEP GROTH STRIP GALAXY REDSHIFT SURVEY. III. REDSHIFT CATALOG AND PROPERTIES OF GALAXIES. The Astrophysical Journal, 620(2), 595-617. doi:10.1086/427256
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  The Deep Extragalactic Evolutionary Probe (DEEP) is a series of spectroscopic surveys of faint galaxies, targeted at understanding the properties and clustering of galaxies at redshifts z ~ 1. We present the redshift catalog of the DEEP1 Groth Strip pilot phase of this project, a Keck LRIS survey of faint galaxies in the Groth Survey Strip imaged with HST WFPC2. The redshift catalog and data, including reduced spectra, are made publicly available through a Web-accessible database. The catalog contains 658 secure galaxy redshifts with a median z = 0.65. The distribution of these galaxies shows large-scale structure walls to z ~ 1. We find a bimodal distribution in the galaxy color-magnitude diagram that persists to the same distance. A similar color division has been seen locally by the SDSS and to z ~ 1 by the COMBO-17 survey. The HST imaging allows us to measure structural properties of the galaxies, and we find that the color division corresponds generally to a structural division. Most red galaxies, ~75%, are centrally concentrated, with a red bulge or spheroidal stellar component, while blue galaxies usually have exponential profiles. However, there are two subclasses of red galaxies that are not bulge dominated: edge-on disks and a second category that we term diffuse red galaxies (DIFRGs). Comparison to a local sample drawn from the RC3 suggests that distant edge-on disks are similar in appearance and frequency to those at low redshift, but analogs of DIFRGs are rare among local red galaxies. DIFRGs have significant emission lines, indicating that they are reddened mainly by dust rather than age. The DIFRGs in our sample are all at z > 0.64, suggesting that DIFRGs are more prevalent at high redshifts; they may be related to the dusty or irregular extremely red objects beyond z > 1.2 that have been found in deep K-selected surveys. We measure the color evolution of both red and blue galaxies by comparing our U - B colors to those from the RC3. For red galaxies, we find a reddening of only 0.11 mag from z ~ 0.8 to now, about half the color evolution measured by COMBO-17. Larger, more carefully defined samples with better colors are needed to improve this measurement. Reconciling evolution in color, luminosity, mass, morphology, and star formation rates will be an active topic of future research.
• Amico, P., Barger, A. J., Capak, P., Chaffee, F. H., Coil, A. L., Conrad, A., Cooper, M. C., Cowie, L. L., Davis, M., Faber, S. M., Goodrich, R. W., Hu, E. M., Koo, D. C., Kwok, S., Lyke, J. E., Mader, J. A., Mignant, D. L., Newman, J. A., Songaila, A., , Tran, H. D., et al. (2004). The Team Keck Treasury Redshift Survey of the GOODS-North Field. The Astronomical Journal, 127(6), 3121-3136. doi:10.1086/420999
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  We report the results of an extensive imaging and spectroscopic survey in the Great Observatories Origins Deep Survey (GOODS)-North field completed using DEIMOS on the Keck II telescope. Observations of 2018 targets in a magnitude-limited sample of 2911 objects to RAB = 24.4 yield secure redshifts for a sample of 1440 galaxies and active galactic nuclei (AGNs) plus 96 stars. In addition to redshifts and associated quality assessments, our catalog also includes photometric and astrometric measurements for all targets detected in our R-band imaging survey of the GOODS-North region. We investigate various sources of incompleteness and find the redshift catalog to be 53% complete at its limiting magnitude. The median redshift of z = 0.65 is lower than in similar deep surveys because we did not select against low-redshift targets. Comparison with other redshift surveys in the same field, including a complementary Hawaii-led DEIMOS survey, establishes that our velocity uncertainties are as low as σ ≈ 40 km s-1 for red galaxies and that our redshift confidence assessments are accurate. The distributions of rest-frame magnitudes and colors among the sample agree well with model predictions out to and beyond z = 1. We will release all survey data, including extracted one-dimensional and sky-subtracted two-dimensional spectra, thus providing a sizable and homogeneous database for the GOODS-North field, which will enable studies of large-scale structure, spectral indices, internal galaxy kinematics, and the predictive capabilities of photometric redshifts.
• Caretta, C. A., Maia, M. A., & Willmer, C. N. (2004). The aquarius superclusters. II. Spectroscopic and photometric data. Astronomical Journal, 128(Issue 6). doi:10.1086/426005
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  We present spectroscopic and photometric data for 920 galaxies selected in 68 fields of the Aquarius Cluster Catalog. Typically, the 15 brightest candidate members with magnitudes in the range 16 < bj < 21 were selected for observations, and ∼71% turn out to be cluster members. Using the new redshift determinations, we assign galaxies to groups and clusters, and by including data from the literature we calculate systemic velocities and velocity dispersions for 74 clusters, each with redshifts measured for at least six individual galaxies.
• Coil, A. L., Conselice, C. J., Cooper, M. C., Davis, M., Ellis, R. S., Faber, S. M., Finkbeiner, D. P., Guhathakurta, P., Kaiser, N., Koo, D. C., Madgwick, D. S., Newman, J. A., Phillips, A. C., Steidel, C. C., Weiner, B. J., Willmer, C. N., & Yan, R. (2004). The DEEP2 Galaxy Redshift Survey: Clustering of Galaxies in Early Data. The Astrophysical Journal, 609(2), 525-538. doi:10.1086/421337
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  We measure the two-point correlation function ξ(rp, π) in a sample of 2219 galaxies between z = 0.7 and 1.35 to a magnitude limit of RAB = 24.1 from the first season of the DEEP2 Galaxy Redshift Survey. From ξ(rp, π) we recover the real-space correlation function, ξ(r), which we find can be approximated within the errors by a power law, ξ(r) = (r/r0)-γ, on scales ~0.1-10 h-1 Mpc. In a sample with an effective redshift of zeff = 0.82, for a ΛCDM cosmology we find r0 = 3.53 ± 0.81 h-1 Mpc (comoving) and γ = 1.66 ± 0.12, while in a higher redshift sample with zeff = 1.14 we find r0 = 3.12 ± 0.72 h-1 Mpc and γ = 1.66 ± 0.12. These errors are estimated from mock galaxy catalogs and are dominated by the cosmic variance present in the current data sample. We find that red, absorption-dominated, passively evolving galaxies have a larger clustering scale length, r0, than blue, emission-line, actively star-forming galaxies. Intrinsically brighter galaxies also cluster more strongly than fainter galaxies at z 1. Our results imply that the DEEP2 galaxies have an effective bias b = 0.96 ± 0.13 if σ8DM = 1 today or b = 1.19 ± 0.16 if σ8DM = 0.8 today. This bias is lower than that predicted by semianalytic simulations at z 1, which may be the result of our R-band target selection. We discuss possible evolutionary effects within our survey volume, and we compare our results with galaxy-clustering studies at other redshifts, noting that our star-forming sample at z 1 has selection criteria very similar to the Lyman break galaxies at z 3 and that our red, absorption-line sample displays a clustering strength comparable to the expected clustering of the Lyman break galaxy descendants at z 1. Our results demonstrate that galaxy-clustering properties as a function of color, spectral type, and luminosity seen in the local universe were largely in place by z 1.
• Coil, A. L., Conselice, C. J., Cooper, M. C., Davis, M., Faber, S. M., Gerke, B. F., Guhathakurta, P., Koo, D. C., Lin, L., Newman, J. A., Patton, D. R., Willmer, C. N., & Yan, R. (2004). The DEEP2 Galaxy Redshift Survey: Evolution of Close Galaxy Pairs and Major-Merger Rates up to z ~ 1.2. The Astrophysical Journal, 617(1), L9-L12. doi:10.1086/427183
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  We derive the close, kinematic pair fraction and merger rate up to redshift z ~ 1.2 from the initial data of the DEEP2 Redshift Survey. Assuming a mild luminosity evolution, the number of companions per luminous galaxy is found to evolve as (1 + z)m, with m = 0.51 ± 0.28; assuming no evolution, m = 1.60 ± 0.29. Our results imply that only 9% of present-day L* galaxies have undergone major mergers since z ~ 1.2 and that the average major merger rate is about 4 × 10-4 h3 Mpc-3 Gyr-1 for z ~ 0.5-1.2. Most previous studies have yielded higher values.
• Faber, S. M., Glassman, T. M., Koo, D. C., Larkin, J. E., Metevier, A. J., Norton, S. A., Raschke, L. M., Steinbring, E., & Willmer, C. N. (2004). Keck Adaptive Optics Imaging of 0.5 < z < 1 Field Galaxies from the Hubble Space Telescope Archive. Astrophysical Journal Supplement Series, 155(1), 15-25. doi:10.1086/424445
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  We have employed natural guide star adaptive optics (AO) on the Keck II telescope to obtain near-infrared (H and K') images of three field galaxies, each of redshift greater than 0.5. These are among the highest-redshift non-active disk galaxies to be imaged with AO. Each of the galaxies was chosen because it had been observed previously with the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) by others. Our AO images in the near-infrared (NIR) closely match both the depth and high spatial resolution of those optical data. Combining the archival V and I data with our new H and K' images potentially produces a long-wavelength baseline at uniform resolution. The NIR data probe emission well longward of the 4000 A break at these redshifts and provide stellar fluxes less contaminated by dust. We fitted two-dimensional galaxy bulge+disk models simultaneously in all bands and compare stellar population synthesis modeling to the photometry of these separated components. This is an initial foray into combining HST and AO imaging to produce a high spatial resolution multicolor data set for a large sample of faint galaxies. Our pilot program shows that NIR AO images from large ground-based observatories, augmented by HST images in the optical, can in principle provide a powerful tool for the analysis of faint field galaxies. However, the AO data signal-to-noise ratio will have to be increased, and AO PSFs need to be controlled more carefully than they were here.
• Faber, S. M., Kobulnicky, H. A., Koo, D. C., Phillips, A. C., Sarajedini, V. L., Simard, L., Vogt, N. P., Weiner, B. J., & Willmer, C. N. (2004). Erratum: “The DEEP Groth Strip Survey. VII. The Metallicity of Field Galaxies at 0.26 < z < 0.82 and the Evolution of the Luminosity-Metallicity Relation” (ApJ, 599, 1006 [2003]). The Astrophysical Journal, 610(2), 1234-1237. doi:10.1086/422574
• Machado, R. S., Maia, M. A., Rossetto, B. M., & Willmer, C. N. (2004). Effects of the Environment on the Properties of Seyfert Galaxies. Proceedings of the International Astronomical Union, 2004(IAUS222), 435-438. doi:10.1017/s1743921304002819
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  We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey – SSRS2. We use the entire SSRS2 catalog to investigate the correlation between the presence of AGN with host environment. The AGN phenomenon is more strongly correlated with the internal host properties than with the external environment. In particular, we find that Seyferts reside in more luminous galaxies, and are twice as frequent in barred galaxies and systems showing signs of advanced merger condition, when compared to a control sample.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html
• Alonso, M. V., Bernardi, M., Chaves, O. L., Costa, L. N., Maia, M. A., Pellegrini, P. S., Rit, C., Rite, C., Wegner, G., & Willmer, C. N. (2003). Redshift-Distance Survey of Early-Type Galaxies: Spectroscopic Data. The Astronomical Journal, 126(5), 2268-2280. doi:10.1086/378959
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  We present central velocity dispersions and Mg2 line indices for an all-sky sample of ~1178 elliptical and S0 galaxies, of which 984 had no previous measures. This sample contains the largest set of homogeneous spectroscopic data for a uniform sample of elliptical galaxies in the nearby universe. These galaxies were observed as part of the ENEAR project, designed to study the peculiar motions and internal properties of the local early-type galaxies. Using 523 repeated observations of 317 galaxies obtained during different runs, the data are brought to a common zero point. These multiple observations, taken during the many runs and different instrumental setups employed for this project, are used to derive statistical corrections to the data and are found to be relatively small, typically 5% of the velocity dispersion and 0.01 mag in the Mg2 line strength. Typical errors are about 8% in velocity dispersion and 0.01 mag in Mg2, in good agreement with values published elsewhere.
• Alonso, M. V., Bernardi, M., Costa, L. N., Maia, M. A., Pellegrini, P. S., Wegner, G., & Willmer, C. N. (2003). Redshift-Distance Survey of Early-Type Galaxies: Circular Aperture Photometry. The Astronomical Journal, 125(5), 2307-2324. doi:10.1086/374766
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  We present R-band CCD photometry for 1332 early-type galaxies, observed as part of the ENEAR survey of peculiar motions using early-type galaxies in the nearby universe. Circular apertures are used to trace the surface brightness profiles, which are then fitted by a two-component bulge-disk model. From the fits, we obtain the structural parameters required to estimate galaxy distances using the Dn-σ and fundamental plane relations. We find that about 12% of the galaxies are well represented by a pure r1/4 law, while 87% are best fitted by a two-component model. There are 356 repeated observations of 257 galaxies obtained during different runs that are used to derive statistical corrections and bring the data to a common system. We also use these repeated observations to estimate our internal errors. The accuracy of our measurements are tested by the comparison of 354 galaxies in common with other authors. Typical errors in our measurements are 0.011 dex for log Dn, 0.064 dex for log re, 0.086 mag arcsec-2 for μe, and 0.09 for m, comparable to those estimated by other authors. The photometric data reported here represent one of the largest high-quality and uniform all-sky samples currently available for early-type galaxies in the nearby universe, especially suitable for peculiar motion studies.
• Cardiel, N., Elbaz, D., Gallego, J., Koo, D. C., Phillips, A. C., Schiavon, R. P., & Willmer, C. N. (2003). A multiwavelength approach to the star formation rate estimation in galaxies at intermediate redshifts. The Astrophysical Journal, 584(1), 76-99. doi:10.1086/345594
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  We use a sample of seven starburst galaxies at intermediate redshifts (z similar to 0.4 and 0.8) with observations ranging from the observed ultraviolet to 1.4 GHz, to compare the star formation rate (SFR) estimators that are used in the different wavelength regimes. We find that extinction-corrected Halpha underestimates the SFR, and the degree of this underestimation increases with the infrared luminosity of the galaxies. Galaxies with very different levels of dust extinction as measured with SFRIR/SFR(Halpha, uncorrected for extinction) present a similar attenuation A [Halpha], as if the Balmer lines probed a different region of the galaxy than the one responsible for the bulk of the IR luminosity for large SFRs. In addition, SFR estimates derived from [O II] lambda3727 match very well those inferred from Halpha after applying the metallicity correction derived from local galaxies. SFRs estimated from the UV luminosities show a dichotomic behavior, similar to that previously reported by other authors in galaxies at z less than or similar to 0.4. Here we extend this result up to z similar to 0.8. Finally, one of the studied objects is a luminous compact galaxy (LCG) that may be suffering similar dust-enshrouded star formation episodes. These results highlight the relevance of quantifying the actual L-IR of LCGs, as well as that of a much larger and generic sample of luminous infrared galaxies, which will be possible after the launch of SIRTF.
• Coil, A. L., Connolly, A. J., Connolly, A., Conselice, C. J., Cooper, M. C., Davis, M., Eisenhardt, P. R., Eisenhardt, P., Ellis, R. S., Faber, S. M., Finkbeiner, D. P., Gerke, B. F., Guhathakurta, P., Kaiser, N., Koo, D. C., Luppino, G. A., Newman, J. A., Phillips, A. C., Schiavon, R. P., , Steidel, C. C., et al. (2003). Science objectives and early results of the DEEP2 Redshift Survey. Astronomical Telescopes and Instrumentation, 4834, 161-172. doi:10.1117/12.457897
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  The DEIMOS spectrograph has now been installed on the Keck-II telescope and commissioning is nearly complete. The DEEP2 Redshift Survey, which will take approximately 120 nights at the Keck Observatory over a three year period and has been designed to utilize the power of DEIMOS, began in the summer of 2002. The multiplexing power and high efficiency of DEIMOS enables us to target 1000 faint galaxies per clear night. Our goal is to gather high-quality spectra of ≈ 60,000 galaxies with z>0.75 in order to study the properties and large scale clustering of galaxies at z ≈ 1. The survey will be executed at high spectral resolution, R=λ/Δλ ≈ 5000, allowing us to work between the bright OH sky emission lines and to infer linewidths for many of the target galaxies (for several thousand objects, we will obtain rotation curves as well). The linewidth data will facilitate the execution of the classical redshift-volume cosmological test, which can provide a precision measurement of the equation of state of the Universe. This talk reviews the project, summarizes our science goals and presents some early DEIMOS data.
• Coil, A. L., Conselice, C. J., Cooper, M. C., Davis, M., Ellis, R. S., Faber, S. M., Finkbeiner, D. P., Gerke, B. F., Guhathakurta, P., Kaiser, N., Koo, D. C., Madgwick, D. S., Newman, J. A., Phillips, A. C., Steidel, C. C., Weiner, B. J., Willmer, C. N., & Yan, R. (2003). The DEEP2 Galaxy Redshift Survey: Spectral Classification of Galaxies at z ∼ 1. The Astrophysical Journal, 599(2), 997-1005. doi:10.1086/379626
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  We present a principal component analysis (PCA)-based spectral classification, η, for the first 5600 galaxies observed in the DEEP2 Redshift Survey. This parameter provides a very pronounced separation between absorption- and emission-dominated galaxy spectra—corresponding to passively evolving and actively star-forming galaxies in the survey, respectively. In addition it is shown that, despite the high resolution of the observed spectra, this parameter alone can be used to quite accurately reconstruct any given galaxy spectrum, suggesting there are not many "degrees of freedom" in the observed spectra of this galaxy population. It is argued that this form of classification, η, will be particularly valuable in making future comparisons between high- and low-redshift galaxy surveys for which very large spectroscopic samples are now readily available, particularly when used in conjunction with high-resolution spectral synthesis models, which will be made public in the near future. We also discuss the relative advantages of this approach to distant galaxy classification compared to other methods such as colors and morphologies. Finally, we compare the classification derived here with that adopted for the 2dF Galaxy Redshift Survey and in so doing show that the two systems are very similar. This will be particularly useful in subsequent analyses when making comparisons between results from each of these surveys to study evolution in the galaxy populations and large-scale structure.
• Faber, S. M., Gebhardt, K., Illingworth, G. D., Im, M., Koo, D. C., Phillips, A. C., Sarajedini, V. L., Simard, L., Vogt, N. P., Weiner, B. J., & Willmer, C. N. (2003). The DEEP Groth Strip Survey. IX. Evolution of the Fundamental Plane of Field Galaxies. The Astrophysical Journal, 597(1), 239-262. doi:10.1086/378401
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  Fundamental plane studies provide an excellent means of understanding the evolutionary history of early-type galaxies. Using the Low Resolution Imaging Spectrograph on the Keck Telescope, we obtained internal stellar kinematic information for 36 field galaxies in the Groth Strip, 21 early-type and 15 disk galaxies. Their redshifts range from 0.3 to 1.0, with a median redshift of 0.8. The slope of the relation shows no difference compared with the local slope. However, there is significant evolution in the zero-point offset; an offset due to evolution in magnitude requires a 2.4 mag luminosity brightening at z = 1. We see little differences of the offset with bulge fraction, which is a good surrogate for galaxy type. Correcting for the luminosity evolution reduces the orthogonal scatter in the fundamental plane to 8%, consistent with the local scatter. This scatter is measured for our sample and does not include results from other studies, which may have different selection effects. The difference in the degree of evolution between our field sample and published cluster galaxies suggests a more recent formation epoch, around z = 1.5 for field galaxies compared to z > 2.0 for cluster galaxies. The magnitude difference implies that the field early-type galaxies are about 2 Gyr younger than the cluster ellipticals using standard single-burst models. However, the same models imply a significant change in the rest-frame U-B color from then to the present, which is not seen in our sample. Continuous low-level star formation, however, would serve to explain the constant colors over this large magnitude change. A consistent model has 7% of the stellar mass created after the initial burst, using an exponentially decaying star formation rate with an e-folding time of 5 Gyr.
• Faber, S. M., Kobulnicky, H. A., Koo, D. C., Phillips, A. C., Sarajedini, V. L., Simard, L., Vogt, N. P., Weiner, B. J., & Willmer, C. N. (2003). The DEEP Groth Strip Survey. VII. The Metallicity of Field Galaxies at 0.26 < z < 0.82 and the Evolution of the Luminosity-Metallicity Relation. The Astrophysical Journal, 599(2), 1006-1030. doi:10.1086/379360
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  Using spectroscopic data from the Deep Extragalactic Evolutionary Probe Groth Strip Survey (DGSS), we analyze the gas-phase oxygen abundances in the warm ionized medium for 64 emission-line field galaxies in the redshift range 0.26 -19) end of the sample and is vanishingly small for objects at the high-luminosity end of the sample (MB ~ -22). We compare these data to simple single-zone, exponential-infall PEGASE2 models, which follow the chemical and luminous evolution of galaxies from formation to z = 0. A narrow range of model parameters can qualitatively produce the slope of the L-Z relation and the observed evolution of slope and zero point with redshift when at least two of the following are true: (1) low-mass galaxies have lower effective chemical yields than massive galaxies, (2) low-mass galaxies assemble on longer timescales than massive galaxies, and (3) low-mass galaxies begin the assembly process at a later epoch than massive galaxies. The single-zone models do a reasonable job of reproducing the observed evolution for the low-luminosity galaxies (MB ~ -19) in our sample but fail to predict the relative lack of evolution in the L-Z plane observed for the most luminous galaxies (MB ~ -22). More realistic multizone models will be required to explain the chemoluminous evolution of large galaxies.
• Machado, R. S., Maia, M. A., & Willmer, C. N. (2003). The Seyfert Population in the Local Universe. The Astronomical Journal, 126(4), 1750-1762. doi:10.1086/378360
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  The magnitude-limited catalog of the Southern Sky Redshift Survey (SSRS2) is used to characterize the properties of galaxies hosting active galactic nuclei (AGNs). Using emission-line ratios, we identify a total of 162 (3%) Seyfert galaxies out of the parent sample with 5399 galaxies. The sample contains 121 Seyfert 2 galaxies and 41 Seyfert 1 galaxies. The SSRS2 Seyfert galaxies are predominantly in spirals of types Sb and earlier or in galaxies with perturbed appearance as the result of strong interactions or mergers. Seyfert galaxies in this sample are twice as common in barred hosts as the non-Seyfert galaxies. By assigning galaxies to groups using a percolation algorithm, we find that the Seyfert galaxies in the SSRS2 are more likely to be found in binary systems when compared with galaxies in the SSRS2 parent sample. However, there is no statistically significant difference between the Seyfert and SSRS2 parent sample when systems with more than two galaxies are considered. The analysis of the present sample suggests that there is a stronger correlation between the presence of the AGN phenomenon with internal properties of galaxies (morphology, presence of bar, luminosity) than with environmental effects (local galaxy density, group velocity dispersion, nearest neighbor distance).
• Alonso, M. V., Bernardi, M., Costa, L. N., Maia, M. A., Pellegrini, P. S., Rite, C., Wegner, G., & Willmer, C. N. (2002). Redshift-Distance Survey of Early-Type Galaxies. I. The ENEARc Cluster Sample*. The Astronomical Journal, 123(6), 2990-3017. doi:10.1086/340463
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  This paper presents data on the ENEARc subsample of the larger ENEAR survey of nearby early-type galaxies. The ENEARc galaxies belong to clusters and were specifically chosen to be used for the construction of a Dn-� template. The ENEARc sample includes new measurements of spectroscopic and photometric parameters (redshift, velocity dispersion, line index Mg2, and the angular diameter dn), as well as data from the literature. New spectroscopic data are given for 229 cluster early-type galaxies, and new photometry is presented for 348 objects. Repeat and overlap observations with external data sets are used to construct a final merged catalog consisting of 640 early-type galaxies in 28 clusters. Objective criteria, based on catalogs of groups of galaxies derived from complete redshift surveys of the nearby universe, are used to assign galaxies to clusters. In a companion paper, these data are used to construct the template Dn-� distance relation for early-type galaxies, which has been used to estimate galaxy distances and derive peculiar velocities for the ENEAR all-sky sample.
• Alonso, M. V., Bernardi, M., Costa, L. N., Maia, M. A., Pellegrini, P. S., Rite, C., Wegner, G., & Willmer, C. N. (2002). Redshift-Distance Survey of Early-Type Galaxies. II. The Dn-σ Relation*. The Astronomical Journal, 123(5), 2159-2182. doi:10.1086/339697
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  R-band photometric and velocity dispersion measurements for a sample of 452 elliptical and S0 galaxies in 28 clusters are used to construct a template Dn-� relation. This template relation is constructed by combining the data from the 28 clusters, under the assumption that galaxies in different clusters have similar properties. The photometric and spectroscopic data used consist of new as well as published measurements, converted to a common system, as presented in an accompanying paper. The resulting direct relation, corrected for incompleteness bias, is logDn ¼ 1:203 log � þ 1:406; the zero point has been defined by requiring distant clusters to be at rest relative to the cosmic microwave background. This zero point is consistent with the value obtained by using the distance to Virgo as determined by the Cepheid period-luminosity relation. This new Dn-�relation leads to a peculiar velocity of � 72 � 189 km s � 1 for the Coma Cluster. The scatter in the distance relation corresponds to a distance error of about 20%, comparable to the values obtained for the fundamental plane relation. Correlations between the scatter and residuals of the Dn-� relation with other parameters that characterize the cluster and/or the galaxy stellar population are also analyzed. The direct and inverse relations presented here have been used in recent studies of the peculiar velocity field mapped by the ENEAR all-sky sample.
• Alonso, M. V., Chiappini, C., Costa, M. L., Maia, G., Ogando, R. L., Pellegrini, P. S., Rite, C., Schiavon, R. P., & Willmer, C. N. (2002). First Results of Metallicity Gradients in Elliptical Galaxies. Revista Mexicana De Astronomia Y Astrofisica, 14(1), 78-78.
• Caretta, C. A., Kawasaki, W., Maia, M. A., & Willmer, C. N. (2002). The Aquarius Superclusters. I. Identification of Clusters and Superclusters. The Astronomical Journal, 123(3), 1200-1215. doi:10.1086/338894
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  We study the distribution of galaxies and galaxy clusters in a 10° × 6° field in the Aquarius region. In addition to 63 clusters in the literature, we have found 39 new candidate clusters using a matched-filter technique and a counts-in-cells analysis. From redshift measurements of galaxies in the direction of these cluster candidates, we present new mean redshifts for 31 previously unobserved clusters, while improved mean redshifts are presented for 35 other systems. About 45% of the projected density enhancements are due to the superposition of clusters and/or groups of galaxies along the line of sight, but we could confirm for 72% of the cases that the candidates are real physical associations similar to the ones classified as rich galaxy clusters. On the other hand, the contamination due to galaxies not belonging to any concentration or located only in small groups along the line of sight is ~10%. Using a percolation radius of 10 h-1 Mpc (spatial density contrast of about 10), we detect two superclusters of galaxies in Aquarius, at z ~ 0.086 and 0.112, respectively, with five and 14 clusters. The latter supercluster may represent a space overdensity of about 160 times the average cluster density as measured from the Abell et al. cluster catalog and is possibly connected to a 40 h-1 Mpc filament from z ~ 0.11 to 0.14.
• Caretta, C. A., Maia, M. A., & Willmer, C. N. (2002). The Aquarius Superclusters. Revista Mexicana De Astronomia Y Astrofisica, 14, 76-76.
• Faber, S. M., Gebhardt, K., Illingworth, G. D., Im, M., Koo, D. C., Phillips, A. C., Sarajedini, V. L., Simard, L., Vogt, N. P., & Willmer, C. N. (2002). The DEEP Groth Strip Survey. X. Number Density and Luminosity Function of Field E/S0 Galaxies at z < 1. The Astrophysical Journal, 571(1), 136-171. doi:10.1086/339854
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  We present the luminosity function and color-redshift relation of a magnitude-limited sample of 145 mostly red field E/S0 galaxies at z 1 from the DEEP Groth Strip Survey (GSS). Using nearby galaxy images as a training set, we develop a quantitative method to classify E/S0 galaxies based on smoothness, symmetry, and bulge-to-total light ratio. Using this method, we identify 145 E/S0's at 16.5 < I < 22 within the GSS, for which 44 spectroscopic redshifts (zspec) are available. Most of the galaxies with spectroscopic redshifts (86%) form a "red envelope" in the redshift-color diagram, consistent with predictions of spectral synthesis models in which the dominant stellar population is formed at redshifts z 1.5. We use the tight correlation between V-I and zspec for this red subset to estimate redshifts of the remaining E/S0's to an accuracy of ~10%, with the exception of a small number (16%) of blue interlopers at low redshift that are quantitatively classified as E/S0's but are not contained within the red envelope. Constructing a luminosity function of the full sample of 145 E/S0's, we find that there is about 1.1-1.9 mag brightening in rest-frame B-band luminosity back to z 0.8 from z = 0, consistent with other studies. Together with the red colors, this brightening is consistent with models in which the bulk of stars in red field E/S0's formed before zfor 1.5 and have been evolving rather quiescently, with few large starbursts since then. Evolution in the number density of field E/S0 galaxies is more difficult to measure, and uncertainties in the raw counts and their ratio to local samples might amount to as much as a factor of 2. Within that uncertainty, the number density of red E/S0's to z 0.8 seems relatively static, being comparable to or perhaps moderately less than that of local E/S0's, depending on the assumed cosmology. A doubling of E/S0 number density since z = 1 can be ruled out with high confidence (97%) if Ωm = 1. Taken together, our results are consistent with the hypothesis that the majority of luminous field E/S0's were already in place by z ~ 1, that the bulk of their stars were already fairly old, and that their number density has not changed by large amounts since then.
• Faber, S. M., Illingworth, G. D., Im, M., Koo, D. C., Phillips, A. C., Sarajedini, V. L., Simard, L., Vogt, N. P., Weiner, B. J., & Willmer, C. N. (2002). The DEEP Groth Strip Survey. II. Hubble Space Telescope Structural Parameters of Galaxies in the Groth Strip. Astrophysical Journal Supplement Series, 142(1), 1-33. doi:10.1086/341399
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  The quantitative morphological classification of distant galaxies is essential to the understanding of the evolution of galaxies over the history of the universe. This paper presents Hubble Space Telescope WFPC2 F606W and F814W photometric structural parameters for 7450 galaxies in the Groth Strip. These parameters are based on a two-dimensional bulge + disk surface brightness model and were obtained using an automated reduction and analysis pipeline described in detail here. A first set of fits was performed separately in each bandpass, and a second set of fits was performed simultaneously on both bandpasses. The information produced by these two types of fits can be used to explore different science goals. Systematic and random fitting errors in all structural parameters as well as bulge and disk colors are carefully characterized through extensive sets of simulations. The results of these simulations are given in catalogs similar to the real science catalogs so that both real and simulated measurements can be sampled according to the same selection criteria to show biases and errors in the science data subset of interest. The effects of asymmetric structures on the recovered bulge+disk fitting parameters are also explored through simulations. The full multidimensional photometric survey selection function of the Groth Strip is also computed. This selection function, coupled to bias maps from simulations, provides a complete and objective reproduction of the observational limits, and these limits can be applied to theoretical predictions from galaxy evolution models for direct comparisons with the data.
• Machado, R. S., Maia, G., & Willmer, C. N. (2002). The Population of Seyfert Galaxies in the Local Universe. Revista Mexicana De Astronomia Y Astrofisica, 14(1), 77-77.
• Alonso, M. V., Bernardi, M., Branchini, E., Costa, L. N., Nusser, A., Pellegrini, P. S., Wegner, G., & Willmer, C. N. (2001). Comparison of the ENEAR peculiar velocities with the PSCz gravity field. Monthly Notices of the Royal Astronomical Society, 320(3), L21-L24. doi:10.1046/j.1365-8711.2001.04107.x
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  We present a comparison between the peculiar velocity field measured from the ENEAR all-sky D-n-sigma catalogue and that derived from the galaxy distribution of the IRAS Point Source Catalog Redshift Survey (PSCz). The analysis is based on a modal expansion of these data in redshift space by means of spherical harmonics and Bessel functions. The effective smoothing scale of the expansion is almost linear with redshift reaching 1500 km s(-1) at 3000 km s(-1). The general flow patterns in the filtered ENEAR and PSCz velocity fields agree well within 6000 km s(-1), assuming a linear biasing relation between the mass and the PSCz galaxies. The comparison allows us to determine the parameter beta=Omega (0.6)b, where Omega is the cosmological density parameter and b is the linear biasing factor. A likelihood analysis of the ENEAR and PSCz modes yields beta =0.5 +/-0.1, in good agreement with values obtained from Tully-Fisher surveys.
• Faber, S. M., Gebhardt, K., Im, M., Koo, D. C., Phillips, A. C., Schiavon, R. P., Simard, L., & Willmer, C. N. (2001). Are There Blue, Massive E/S0 Galaxies at z < 1? Kinematics of Blue Spheroidal Galaxy Candidates. The Astronomical Journal, 122(2), 750-763. doi:10.1086/322081
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  Several recent studies find that 10%–50% of morphologically selected field early-type galaxies at redshifts z 1 have blue colors indicative of recent star formation. Such "blue spheroids" might be massive early-type galaxies with active star formation, perhaps induced by recent merger events. Alternatively, they could be starbursting, low-mass spheroids. To distinguish between these two choices, we have selected 10 "Blue Spheroid Candidates" (BSCs) from a quantitatively selected E/S0 sample to study their properties, including kinematics from Keck spectra obtained as part of the DEEP Groth Strip Survey (GSS). Most BSCs (70%) turn out to belong to two broad categories, while the remaining objects are likely to be misclassified objects. Type 1 BSCs have underlying red stellar components with bluer inner components. Type 2 BSCs do not show an obvious sign of the underlying red stellar component, and their overall colors are quite blue [(U-B)rest < 0]. Both type 1 and type 2 BSCs have internal velocity dispersions measured from emission lines σ 80 km s-1 and estimated dynamical masses of only a few ×1010 M⊙ or less. For type 1 BSCs, we estimate σ of the red component using the fundamental plane relation of distant field absorption-line galaxies and find that these σ estimates are similar to the σ measured from emission lines. Overall, we conclude that our type 1 and type 2 BSCs are more likely to be star-forming low-mass spheroids than star-forming, massive, early-type galaxies.
• Zaroubi, S., Bernardi, M., Costa, L. N., Hoffman, Y., Alonso, M. V., Wegner, G., Willmer, C. N., & Pellegrini, P. S. (2001). Large-scale power spectrum and structures from the ENEAR galaxy peculiar velocity catalogue. Monthly Notices of the Royal Astronomical Society, 326(1), 375-386. doi:10.1046/j.1365-8711.2001.04605.x
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  We estimate the mass density fluctuations power spectrum (PS) on large scales by applying a maximum likelihood technique to the peculiar velocity data of the recently completed redshift—distance survey of early-type galaxies (hereafter ENEAR). Parametric cold dark matter (CDM)-like models for the PS are assumed, and the best-fitting parameters are determined by maximizing the probability of the model given the measured peculiar velocities of the galaxies, their distances and estimated errors. The method has been applied to CDM models with and without COBE normalization. The general results are in agreement with the high-amplitude power spectra found from similar analyses of other independent all-sky catalogue of peculiar velocity data such as MARK III and SFI, in spite of the differences in the way these samples were selected, the fact that they probe different regions of space and galaxy distances are computed using different distance relations. For example, at k = 0.1 h Mpc−1 the power spectrum value is P(k)Ω1.2 = (6.5 ± 3) × 103(h−1 Mpc)3 and η8 ≡ σ8Ω0.6 = 1.1−0.35+0.2; the quoted uncertainties refer to 3σ error level. We also find that, for ΛCDM and OCDM COBE-normalized models, the best-fitting parameters are confined by a contour approximately defined by Ω h1.3 = 0.377 ± 0.08 and Ω h0.88 = 0.517±0.083 respectively. Γ-shape models, free of COBE normalization, result in the weak constraint of Γ≥0.17 and in the rather stringent constraint of η8 = 1.0 ± 0.25. All quoted uncertainties refer to 3σ confidence level (c.l.). The calculated PS has been used as a prior for Wiener reconstruction of the density field at different resolutions and the three-dimensional velocity field within a volume of radius ≈80 h−1 Mpc. All major structures in the nearby Universe are recovered and are well matched to those predicted from all-sky redshift surveys. The robustness of these features has been tested with constrained realizations (CR). Analysis of the reconstructed three-dimensional velocity field yields a small bulk-flow amplitude (∼160±60 km s−1 at 60 h−1 Mpc) and a very small rms value of the tidal field (∼60 km s−1). The results give further support to the picture that most of the motion of the Local Group arises from mass fluctuations within the volume considered.
• Alonso, M. V., Bernardi, M., Borgani, S., Costa, L. N., Maia, M. A., Pellegrini, P. S., Wegner, G., & Willmer, C. N. (2000). ENEAR REDSHIFT-DISTANCE SURVEY: COSMOLOGICAL CONSTRAINTS. The Astrophysical Journal, 537(1), L1-L4. doi:10.1086/312761
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  We present an analysis of the ENEAR sample of peculiar velocities of field and cluster elliptical galaxies, obtained with Dn-σ distances. We use the velocity correlation function ψ1(r) to analyze the statistics of the field object's velocities, while the analysis of the cluster data is based on the estimate of their rms peculiar velocity Vrms. The results are compared with predictions from cosmological models using linear theory. The statistics of the model velocity field is parameterized by the amplitude η8 = σ8Ω and by the shape parameter Γ of the cold dark matter-like power spectrum. This analysis is performed in redshift space, so as to circumvent the need to address corrections due to inhomogeneous Malmquist bias and to the redshift cutoff adopted in the sample selection. From the velocity correlation statistics, we obtain η8 = 0.51 for Γ = 0.25 at the 2 σ level for one interesting fitting parameter. This result agrees with that obtained from a similar analysis of the SFI I-band Tully-Fisher (TF) survey of field Sc galaxies. Even though less constraining, a consistent result is obtained by comparing the measured Vrms of clusters with linear theory predictions. For Γ = 0.25, we find η8 = 0.63 at 1 σ. Again, this result agrees, within the uncertainties, with that obtained from the SCI cluster sample based on TF distances. Overall, our results point toward a statistical concordance of the cosmic flows traced by spiral and early-type galaxies, with galaxy distances estimated using TF and Dn-σ distance indicators, respectively.
• Alonso, M. V., Bernardi, M., Costa, L. N., Maia, M. A., Pellegrini, P. S., Rite, C., Wegner, G., & Willmer, C. N. (2000). Redshift-Distance Survey of Early-Type Galaxies. I. Sample Selection, Properties, and Completeness*. The Astronomical Journal, 120(1), 95-109. doi:10.1086/301449
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  This is the first in a series of papers describing the recently completed all-sky redshift-distance survey of nearby early-type galaxies (ENEAR) carried out for peculiar velocity analysis. The sample is divided into two parts and consists of 1607 elliptical and lenticular galaxies with cz < 7000 km/s and with blue magnitudes brighter than m_B=14.5 (ENEARm), and of galaxies in clusters (ENEARc). Galaxy distances based on the Dn-sigma and Fundamental Plane (FP) relations are now available for 1359 and 1107 ENEARm galaxies, respectively, with roughly 80% based on new data gathered by our group. The Dn-sigma and FP template distance relations are derived by combining 569 and 431 galaxies in 28 clusters, respectively, of which about 60% are based on our new measurements. The ENEARm redshift-distance survey extends the earlier work of the 7S and the recent Tully-Fisher surveys sampling a comparable volume. In subsequent papers of this series we intend to use the ENEAR sample by itself or in combination with the SFI Tully-Fisher survey to analyze the properties of the local peculiar velocity field and to test how sensitive the results are to different sampling and to the distance indicators. We also anticipate that the homogeneous database assembled will be used for a variety of other applications and serve as a benchmark for similar studies at high-redshift.
• Alonso, M. V., Bernardi, M., Costa, L. N., Maia, M. A., Pellegrini, P. S., Wegner, G., Willmer, C. N., & Zaroubi, S. (2000). Redshift-Distance Survey of Early-Type Galaxies: Dipole of the Velocity Field. The Astrophysical Journal, 537(2), L81-L84. doi:10.1086/312780
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  We use the recently completed redshift-distance survey of nearby early-type galaxies (ENEAR) to measure the dipole component of the peculiar velocity field to a depth of cz ~ 6000 km s-1. The sample consists of 1145 galaxies brighter than mB = 14.5 and with cz ≤ 7000 km s-1, uniformly distributed over the whole sky, and 129 fainter cluster galaxies within the same volume. Most of the Dn-σ distances were obtained from new spectroscopic and photometric observations conducted by this project, ensuring the homogeneity of the data over the whole sky. These 1274 galaxies are objectively assigned to 696 objects—282 groups/clusters and 414 isolated galaxies. We find that within a volume of radius ~6000 km s-1, the best-fitting bulk flow has an amplitude of = 220 ± 60 ± 50 km s-1 in the cosmic microwave background rest frame pointing toward l = 304° ± 16°, b = 25° ± 11°. The error in the amplitude includes statistical, sampling, and possible systematic errors. This solution is in excellent agreement with that obtained by the SFI (I-band field spiral) Tully-Fisher survey. Our results suggest that most of the motion of the Local Group is due to fluctuations within 6000 km s-1, in contrast to recent claims of large-amplitude bulk motions on larger scales.
• Caretta, C. A., Maia, M. A., & Willmer, C. N. (2000). A Quantitative Evaluation of the Galaxy Component of the COSMOS and APM Catalogs. The Astronomical Journal, 119(2), 524-535. doi:10.1086/301193
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  We have carried out an independent quantitative evaluation of the galaxy component of the COSMOS/UKST southern sky object catalog (SSC) and the APM/UKST J Catalogue (APM). Using CCD observations, our results corroborate the accuracy of the photometry of both catalogs, which have an overall dispersion of about 0.2 mag in the range 17 ≤ bJ ≤ 21.5. The SSC presents externally calibrated galaxy magnitudes that follow a linear relation, while the APM instrumental magnitudes of galaxies, calibrated only internally by the use of stellar profiles, require second-order corrections. The completeness of both catalogs in a general field falls rapidly fainter than bJ = 20.0, being slightly better for APM. The 90% completeness level of the SSC is reached between bJ = 19.5 and 20.0, while for APM this happens between bJ = 20.5 and 21.0. Both SSC and APM are found to be less complete in a galaxy cluster field, where completeness reachs 90% in the ranges bJ = 19.0–19.5 and bJ = 19.5–20.0, respectively. Galaxies misclassified as stars in the SSC receive an incorrect magnitude because the stellar ones take saturation into account, besides using a different calibration curve. In both cases, the misclassified galaxies show a large diversity of colors, which range from typical colors of early types to those of blue star-forming galaxies. A possible explanation for this effect is that it results from the combination of low-sampling resolutions with properties of the image classifier for objects with characteristic sizes close to the instrumental resolution. We find that the overall contamination by stars misclassified as galaxies is
• Alonso, M. V., Chaves, O. L., Maia, M. A., Mello, D. F., Mendes, S. O., Rios, L. A., & Willmer, C. N. (1999). Two Galaxy Clusters: A3565 and A3560. The Astronomical Journal, 118(3), 1131-1145. doi:10.1086/301006
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  We report 102 new redshifts and magnitudes for a sample of galaxies to RF ~ 15.5 mag in a 217 × 217 region centered on the galaxy IC 4296, the most luminous member of the A3565 Cluster. Up to the limiting magnitude, we find 29 cluster members and measure a velocity dispersion of σ = 228 km s-1. The estimated total mass for this system is ~3.0 × 1013 h-1 M⊙ [where h = H0/(100 km s-1 Mpc-1)], and its dynamical properties are quite typical of poor clusters presenting X-ray emission. We also find that galaxies with absorption lines are more concentrated toward the center of the cluster, while systems with emission lines are mainly located in the outer parts. The small velocity dispersion of the cluster, coupled with the known presence of an interacting pair of galaxies, and the large extent of the brightest cluster galaxy, could indicate that galaxy formation through mergers may still be underway in this system. The surveyed region also contains galaxies belonging to the Shapley concentration cluster A3560. Within 30' of the cluster center, we detect 32 galaxies, for which we measure a velocity dispersion of 588 km s-1 and a mass of ~2 × 1014 h-1 M⊙. However, because our sample is restricted to galaxies brighter than M*, these values should be considered only as rough estimates.
• Alonso, M. V., Bernardi, M., Costa, L. N., Pellegrini, P. S., Renzini, A., Rite, C., Wegner, G., & Willmer, C. N. (1998). Cluster versus Field Elliptical Galaxies and Clues on Their Formation. The Astrophysical Journal, 508(2), L143-L146. doi:10.1086/311742
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  Using new observations for a sample of 931 early-type galaxies, we investigate whether the Mg2-σ0 relation shows any dependence on the local environment. The galaxies have been assigned to three different environments depending on the local overdensity (clusters, groups, and field); we used our complete redshift database to guide the assignment of galaxies. It is found that cluster, group, and field early-type galaxies follow almost identical Mg2-σ0 relations, with the largest Mg2 zero-point difference (clusters minus field) being only 0.007±0.002 mag. No correlation of the residuals is found with the morphological type or the bulge-to-disk ratio. Using stellar population models in a differential fashion, this small zero-point difference implies a luminosity-weighted age difference of only ~1 Gyr between the corresponding stellar populations, with field galaxies being younger. The mass-weighted age difference could be significantly smaller if minor events of late star formation took place preferentially in field galaxies. We combine these results with the existing evidence for the bulk of stars in cluster early-type galaxies having formed at very high redshift and conclude that the bulk of stars in galactic spheroids had to form at high redshifts (z3), no matter whether such spheroids now reside in low- or high-density regions. The cosmological implications of these findings are briefly discussed.
• Chaves, O. L., Costa, L. N., Fairall, A. P., Geller, M. J., Huchra, J. P., Kurtz, M. J., Latham, D. W., Lipari, S., Maia, M. A., Pellegrini, P. S., Ramella, M., Rite, C., Smith, C., & Willmer, C. N. (1998). The Southern Sky Redshift Survey. The Astronomical Journal, 116(1), 1-7. doi:10.1086/300410
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  We report redshifts, magnitudes, and morphological classifications for 5369 galaxies with mB ≤ 15.5 and for 57 galaxies fainter than this limit, in two regions covering a total of 1.70 sr in the southern celestial hemisphere. The galaxy catalog is drawn primarily from the list of nonstellar objects identified in the Hubble Space Telescope Guide Star Catalog (GSC). The galaxies have positions accurate to ~1'' and magnitudes with an rms scatter of ~0.3 mag. We compute magnitudes (mSSRS2) from the relation between instrumental GSC magnitudes and the photometry by Lauberts & Valentijn. From a comparison with CCD photometry, we find that our system is homogeneous across the sky and corresponds to magnitudes measured at the isophotal level ~26 mag arcsec-2. The precision of the radial velocities is ~40 km s-1, and the redshift survey is more than 99% complete to the mSSRS2 = 15.5 mag limit. This sample is in the direction opposite that of the CfA2; in combination the two surveys provide an important database for studies of the properties of galaxies and their large-scale distribution in the nearby universe.
• Costa, L. N., Geller, M. J., Marzke, R. O., Pellegrini, P. S., & Willmer, C. N. (1998). The Galaxy Luminosity Function at z ≤ 0.05: Dependence on Morphology. The Astrophysical Journal, 503(2), 617-631. doi:10.1086/306011
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  We investigate the dependence of the local galaxy luminosity function on morphology using 5404 galaxies from the recently enlarged Second Southern Sky Redshift Survey (SSRS2). Over the range -22 ≤ MB ≤ -14 (H0 = 100 km s-1 Mpc-1), the luminosity function of early-type galaxies is well fitted by a Schechter function with parameters M -->*=-19.37 -->−0.11+0.10, α=-1.00 -->−0.09+0.09, and * = 4.4 ± 0.8 × 10-3 Mpc-3. The spiral luminosity function is very similar and is well fitted by the parameters M -->*=-19.43 -->−0.08+0.08, α=-1.11 -->−0.06+0.07, and * = 8.0 ± 1.4 × 10-3 Mpc-3 over the same range in absolute magnitude. The flat faint end of the early-type luminosity function is consistent with earlier measurements from the CfA Redshift Survey (Marzke et al.) but is significantly steeper than the slope measured in the Stromlo-APM survey (Loveday et al.). Combined with the increased normalization of the overall LF measured from intermediate-redshift surveys, the flat faint-end slope of the E/S0 LF produces no-evolution models that reproduce the deep Hubble Space Telescope (HST) counts of early-type galaxies remarkably well. However, the observed normalization of the SSRS2 LF is consistent with the low value measured in other local redshift surveys. The cause of this low-redshift anomaly remains unknown. The luminosity function of irregular and peculiar galaxies in the SSRS2 is very steep: M -->*=-19.78 -->−0.50+0.40, α=-1.81 -->−0.24+0.24, and * = 0.2 ± 0.08 × 10-3 Mpc-3. The steep slope at the faint end is consistent with the LFs measured for Sm-Im galaxies in the CfA survey, UV-selected galaxies (Treyer et al.), star-forming field galaxies (Bromley et al.), and the bluest galaxies in the SSRS2 (Marzke & da Costa). As shown by Driver, Windhorst, & Griffiths, the steep LF reduces the observed excess of faint irregulars over no-evolution predictions but cannot explain it entirely.
• Costa, L. N., Pellegrini, P. S., & Willmer, C. N. (1998). Southern Sky Redshift Survey: Clustering of Local Galaxies. The Astronomical Journal, 115(3), 869-884. doi:10.1086/300254
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  We use the two-point correlation function to calculate the clustering properties of the recently completed SSRS2 survey, which probes two well-separated regions of the sky, allowing one to evaluate the sensitivity of sample-to-sample variations. Taking advantage of the large number of galaxies in the combined sample, we also investigate the dependence of clustering on the internal properties of galaxies. The redshift-space correlation function for the combined magnitude-limited sample of the SSRS2 is given by ?(s) = [s/(5.85 h-1 Mpc)]-1.60 for separations in the range 2 h-1 Mpc ? s ? 11 h-1 Mpc, while our best estimate for the real-space correlation function is ?(r) = [r/(5.36 h-1 Mpc)]-1.86. Both are comparable with previous measurements using surveys of optical galaxies over much larger and independent volumes. By comparing the correlation function calculated in redshift and real space, we find that the redshift distortion on intermediate scales is small. This result implies that the observed redshift-space distribution of galaxies is close to that in real space and that ? = ?0.6/b L*) are more clustered than sub-L* galaxies and that the luminosity segregation is scale-independent. We also find that early types are more clustered than late types. However, in the absence of rich clusters, the relative bias between early and late types in real space, bE+S0/bS ~ 1.2, is not as strong as previously estimated. Furthermore, both morphologies present a luminosity-dependent bias, with the early types showing a slightly stronger dependence on luminosity. We also find that red galaxies are significantly more clustered than blue ones, with a mean relative bias of bR/bB ~ 1.4, stronger than that observed for morphology. Finally, by comparing our results with the measurements obtained from the infrared-selected galaxies, we determine that the relative bias between optical and IRAS galaxies in real space is bo/bI ~ 1.4.
• Maia, M. A., Willmer, C. N., & Da Costa, L. N. (1998). Study of a slice at +9° to +15° of declination. I. The neutral hydrogen content of galaxies in loose groups. Astronomical Journal, 115(Issue 1). doi:10.1086/300184
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  We examine the H I content of spiral galaxies in groups by using a catalog of loose groups of galaxies identified in a magnitude-limited sample (mz ≤ 15.7) spanning the range 8h ≤ α ≤ 18h in right ascension and +9° ≤ δ ≤ +15° in declination. The redshift completeness of the galaxy sample is approximately 95%. No significant effect of H I depletion is found, although there may be a hint that the earliest type spirals are slightly deficient.
• Albrecht, P., Alloin, D., Beers, T. C., Bragaglia, A., Calderon, J., Caretta, C. A., Carranza, G., Chatzichristou, E., Claeskens, J. F., Costa, R. D., Diaz, R., Dietrich, M., Dottori, H. A., Elizalde, F., Federspiel, M., Filho, I. R., Ghosh, K. K., Giannuzzo, E., Goldes, G., , Gregorio-hetem, J., et al. (1997). Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. X. Variability of Fairall 9 from optical data. Astrophysical Journal Supplement Series, 112(2), 271-283. doi:10.1086/313046
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  The results of an optical monitoring campaign on the active nucleus in the luminous Seyfert 1 galaxy Fairall 9 are presented. This campaign was undertaken in parallel with ultraviolet spectroscopic moni- toring with the IUE satellite which is described in a separate paper. The primary purpose of this program is to measure the response times (or "" lags II) of the emission lines to continuum variations and thus to extend the range in luminosity of active galactic nuclei (AGNs) for which such measurements have been made. The main conclusions of this work are as follows: 1. Continuum (at 5340 variations of amplitude D12% are detected on timescales as short as D20 Ae ) days. These variations are much larger than the typical uncertainties in the measurements, which are of order D2%. Over D94 days, a factor of 2 change in the nuclear continuum was observed. 2. The optical continuum light curve resembles that of the UV continuum, showing two "" events II of low-amplitude variations with a duration of D70 days and with no measurable lag between the UV and optical continuum light curves. The UV data show a third larger amplitude event that occurred after the optical monitoring had terminated and unfortunately went unobserved in the optical. 3. The Hb emission-line Nux also underwent signi-cant, low-amplitude ("20%) variations. Cross- correlation analysis reveals that Hb lags behind the UV continuum by about 23 days, a value much smaller than what was previously suggested by earlier variability studies. However, this small lag is con- sistent with the lags for the UV lines during this campaign in the sense that the Hb lag is approximately 50% larger than that of Ly aj 1216, as it has been found for lower luminosity AGNs. 4. The Hb di†erence pro-le produced by subtracting the low-state from the high-state data can be described as a two-component structure with blue and red components of similar width (D2500 km s~1) and that appear to vary in phase. Subject headings: galaxies: active E galaxies: individual (Fairall 9) E galaxies: nuclei E galaxies: Seyfert
• Willmer, C. N., & Willmer, C. N. (1997). Estimating galaxy luminosity functions.. The Astronomical Journal, 114(3), 898-912. doi:10.1086/118522
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  view Abstract Citations (87) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Estimating galaxy luminosity functions. Willmer, C. N. A. Abstract In this work a comparison between different galaxy luminosity function estimators by means of Monte-Carlo simulations is presented. The simulations show that the C(-) method of Lynden-Bell (1971) and the STY method derived by Sandage, Tammann & Yahil (1979) are the best estimators to measure the shape of the luminosity function. The simulations also show that the STY estimator has a bias such that the faint-end slope is underestimated for steeper inclinations of the Schechter Function, and that this bias becomes quite severe when the sample contains only a few hundred objects. Overall, the C(-) is the most robust estimator, being less affected by different values of the faint end slope of the Schechter parameterization and sample size. The simulations are also used to compare different estimators of the luminosity function normalization. They demonstrate that most methods bias the recovered mean density towards values which are ~ 20% lower than the input value. Publication: The Astronomical Journal Pub Date: September 1997 DOI: 10.1086/118522 arXiv: arXiv:astro-ph/9707246 Bibcode: 1997AJ....114..898W Keywords: GALAXIES: LUMINOSITY FUNCTION; Astrophysics E-Print: 29 pages, uses AASTeX 4.0 macros. Includes 6 tables and 8 Postscript figures. Scheduled for publication in the AJ 1997 September issue full text sources arXiv | ADS |
• Ellman, N., Koo, D. C., Kurtz, M. J., Szalay, A. S., & Willmer, C. N. (1996). A Medium-deep Survey of a Minislice at the North Galactic Pole. II. The Data. Astrophysical Journal Supplement Series, 104(2), 199. doi:10.1086/192298
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  We report 328 redshifts, bJ magnitudes, and bJ - rF colors of galaxies measured in a redshift survey of a 4° × 0°.67 slice close to the north Galactic pole. The faintest galaxies in this survey have a magnitude of bJ ∼ 20.5. The redshifts present external errors of the order of 70 km s-1, and we estimate that the mean photometry errors are ∼0.2 for magnitudes and ∼0.3 for colors. The redshift completeness level of the sample is of the order of ∼35% at bJ = 20, and part of this rather low completeness is the result of the combination of limitations imposed by the multifiber system with the clustering of galaxies, and an insufficient number of configurations. At the nominal magnitude limit of the survey, we were able to measure redshifts for ∼70% of the galaxies we observed. From the correlation between observed properties of the galaxies in this sample, we demonstrate that the mean surface brightness is a major limiting factor in our ability to measure redshifts of faint objects.
• Maia, M. A., Suzuki, J. A., Da Costa, L. N., Willmer, C. N., & Rite, C. (1996). New southern galaxies with active nuclei. II. Astronomy and Astrophysics Supplement Series, 117(Issue 3). doi:10.1051/aas:1996171
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  This paper contains a list of new AGN candidates identified from the examination of 3500 optical spectra contained in the database of the Southern Sky Redshift Survey Extension (SSRS2). The classification of galaxies was done using standard diagnostics and a total of (5) Seyfert 1, (12) Seyfert 2 and (10) LINERs were found. We also present a list of 60 galaxies for which we could not secure a definite classification, but which might present some level of nuclear activity.
• Willmer, C. N., Koo, D. C., Ellman, N., Kurtz, M. J., & Szalay, A. S. (1996). Erratum: "A Medium-deep Survey of a Minislice at the North Galactic Pole. II. The Data" (ApJS, 104, 199 [1996]). Astrophysical Journal Supplement Series, 107(2), 823-827. doi:10.1086/192383
• Costa, L. N., Fairall, A. P., Freudling, W., Latham, D. W., Pellegrini, P. S., & Willmer, C. N. (1995). The Hydra-Centaurus Region and the Nearby Universe. The Astronomical Journal, 109(1), 61. doi:10.1086/117256
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  In this paper we present maps of the spatial distribution of galaxies in the general direction of the Hydra-Centaurus complex and discuss how that distribution relates to other structures located in the volume within 6000 km s-1 of the Local Group, using a sample of over 5700 galaxies brighter than mB(0) = 14.5 with essentially complete redshift information. Our sample covers about 50% of the sky and allows us to follow structures over large extensions. From the inspection of these maps we find that the galaxies are distributed in a pattern of interconnected structures, many of them with a rather regular wall-like appearance.
• Calderon, J. H., Costa, L. N., Fairall, A. P., Geller, M. J., Huchra, J. P., Kurtz, M. J., Latham, D. W., Marzke, R. O., Pellegrini, P. S., Ramella, M., & Willmer, C. N. (1994). A COMPLETE SOUTHERN SKY REDSHIFT SURVEY. The Astrophysical Journal, 424(1), L1. doi:10.1086/187260
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  We discuss a magnitude-limited redshift survey covering a region around the south Galactic pole (SSRS2). The survey includes 3592 galaxies and covers a region of 1.13 sr to a limiting m(sub B(0)) = 15.5, directly comparable to CfA2. Together, CfA2 and SSR2 cover more than a third of the sky. The northern and southern surveys are remarkably similar. Both contain voids with diameters as large as 5000 km/s. The southern survey contains the Southern Wall, similar to the northern Great Wall. The distributions of velocity dispersions for systems extracted from the SSRS2 and CfA2 surveys are also remarkably similar. For the SSRS2, an inhomogeneity-independent technique yields Schechter luminosity function parameters M(sup *) = -19.50 and alpha = -1.20 (H(sub O) = 100 h km/s/Mpc, h = 1 unless otherwise specified). The steep faint-end slope is probably attributable to bluer galaxies. By examining the normalized density fluctuations in the SSRS2 and CfA2 surveys, we suggest that the combined sample is not yet large enough to be 'fair.' There are large fluctuations in shells at 10,000 km/s.
• Willmer, C. N., Koo, D. C., Szalay, A. S., & Kurtz, M. J. (1994). A medium-deep redshift survey of a minislice at the north Galactic pole. The Astrophysical Journal, 437, 560. doi:10.1086/175021
• Allen, D. A., Banfield, R. M., Bell, S. A., Blades, J. C., Buckley, D. A., Byrne, P. B., Caldwell, J. A., Callanan, P. J., Catchpole, R. M., Collins, C. A., Cumming, R. J., Evans, T. L., Fairall, A. P., Feast, M. W., Freeman, F. F., Holmgren, D., Jones, K., Latham, D. W., Maddox, S., , Meadows, V. S., et al. (1993). Spectroscopic and photometric observations of supernova 1987A – VII. Days 793 to 1770. Monthly Notices of the Royal Astronomical Society, 262(2), 313-324. doi:10.1093/mnras/262.2.313
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  We present spectroscopic and UBV(RI) c JHKLM photometric observations of SN 1987A in the Large Magellanic Cloud made between days 793 and 1770 after the Kamiokande-II neutrino event, as well as some CCD UBV(RI) c photometry from day 640 to day 792, which overlaps the interval covered in the preceding paper of this series. During the period from about day 670 to day 1260, the U- to M- bolometric magnitude (hereafter M UM ) of the supernova and its adjoining circumstellar ring (hereafter «the enclosed supernova») dimmed at an increasingly slower rate than during the preceding interval from day 500 to day 670. The rate of dimming steadily increased again between days 1270 and 1770
• Costa, L. N., Huchra, J. P., Latham, D. W., Pellegrini, P. S., & Willmer, C. N. (1993). The morphological catalogue of galaxies equatorial survey. The Astronomical Journal, 105(5), 1637-1657. doi:10.1086/116543
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  We present 865 redshifts of galaxies located in the equatorial strip delta between -17.5 deg and -2.5 deg in the right ascension range between 20 h and 5 h. Redshifts have been obtained for the complete sample of all 833 galaxies in the Morphological Catalog of Galaxies with magnitudes brighter than m = 14.5 (corresponding approximately to m(Zwicky) = 15.0). This sample also includes three galaxies from other sources with more reliable magnitudes, satisfying this limit, and 29 fainter galaxies, usually companions of the galaxies in the magnitude limited sample. Our maps of a very large volume of nearby space demonstrate a variety of coherent large scale structures which include large voids, 20-50/h Mpc in diameter and large walls at least 70/h Mpc across.
• Calderon, J. H., Costa, L. N., Fairall, A. P., Focardi, P., Latham, D. W., Nunes, M. A., Pellegrini, P. S., Vettolani, G., & Willmer, C. N. (1992). Redshift observations in the Hydra-Centaurus region. The Astronomical Journal, 103(1), 11-27. doi:10.1086/116037
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  406 redshifts are reported for galaxies in the northern galactic hemisphere, south of δ = 0°. A substantial fraction of the observed galaxies are located in the equatorial zone −17.5° ≤ δ ≤ 0°. By combining these new data with those available in the literature it is possible to extend the original CfA redshift survey of galaxies brighter than m B(0) = 14.5 to b = 30°, south of δ = 0°. New data taken at lower galactic latitudes also contribute to the existing surveys of the Hydra-Centaurus complex
• Chan, R., Costa, N. L., Focardi, P., Pellegrini, P. S., & Willmer, C. N. (1991). Studies of nearby poor clusters - A3574 and S753. The Astronomical Journal, 101(1), 57-65. doi:10.1086/115665
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  Une etude de 2 amas appartenant a la concentration Centaurus de galaxies est presentee. La photometrie photographique et les vitesses radiales ont ete obtenues pour les galaxies dans 2 champs carres centres sur les membres les plus brillants de chaque amas. Les parametres dynamiques sont derives pour chaque amas. Aucune sous-structure n'a ete detectee dans les amas. Un modele d'orbite lineaire a 2 corps montre que ces amas ne forment pas un systeme lie, bien que ce resultat soit marginal
• Costa, L. N., Huchra, J. P., Latham, D. W., Pellegrini, P. S., & Willmer, C. N. (1990). Distribution of galaxies in the Southern Galactic Cap. The Astronomical Journal, 99(3), 751. doi:10.1086/115371
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  Observations in the southern galactic hemisphere in the declination range between -17.5 and 2.5 degrees are combined with other available observation. The data set is used to study the spatial distribution of galaxies of a contiguous area of 3.13 sr of the Southern Galactic Cap. An approximately homogeneous magnitude-limited sample of galaxies in the Southern Galactic Cap is constructed from different catalogs. The resulting large scale structure is similar to that of previous surveys in which bright galaxies are distributed on surfaces which intersect at sharp corners and nearly surround voids that are almost empty of galaxies. 29 refs.
• Costa, L. N., Pellegrini, P. S., Santiago, B. X., & Willmer, C. N. (1990). On the Statistical Properties of the Galaxy Distribution. The Astrophysical Journal, 350(1), 95. doi:10.1086/168363
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  The statistical properties of the galaxy distribution in the Northern and Southern Hemisperes are compared, using the redshift catalogs of the CfA Redshift Survey and the Southern Sky Redshift Survey. These surveys probe comparable volumes of space, making it possible to examine whether the spatial distribution of galaxies in these samples has the same general characteristics. Inspite of apparent differences in the clustering pattern, as perceived from a visual inspection of the redshift maps, the results obtained from the application of several statistical indicators to volume-limited samples drawn from both data sets indicate that the clustering properties are, on scales less than about 10/h Mpc (H0 = 100h km/s Mpc), essentially indistinguishable. 32 refs.
• Carvalho, R. R., Costa, L. N., Geary, J. C., Latham, D. W., Maia, M. A., Pellegrini, P. S., & Willmer, C. N. (1989). The ON-CFA Redshift Survey of the Southern Hemisphere. The Astronomical Journal, 97, 315. doi:10.1086/114982
• Costa, L. N., Focardi, P., Pellegrini, P. S., & Willmer, C. N. (1989). Studies of nearby poor clusters - The Eridanus group. The Astronomical Journal, 98, 1531. doi:10.1086/115236
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  Results are reported from dynamical study of the Eridanus group of galaxies. This system is quite prominent in one of the large-scale features found in the recently completed Southern Sky Redshift Survey (da Costa et al., 1988): the Eridanus-Fornax-Dorado filament. The irregualr aspect of Eridanus suggests the existence of subclustering, which is confirmed by statistical tests. These subclusters are bound, suggesting that the system is still condensing from the Hubble flow and may eventually form a cluster of about 10 to the 14th solar mass. By calculating the two-body orbital solution, it is found that the Eridanus complex and the Fornax cluster also form a bound system, although still in the expansion phase. 41 refs.
• Costa, L. N., Latham, D. W., Pellegrini, P. S., & Willmer, C. N. (1989). First results from a deeper survey of a southern redshift slice. The Astrophysical Journal, 344(1), 20-23. doi:10.1086/167772
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  La distribution spatiale des galaxies plus brillantes que m B(0) =15.1, de declinaison −40 o ≤δ≤−30 o , est etudiee
• Chincarini, G., Costa, L. N., Pellegrini, P. S., & Willmer, C. N. (1987). The Centaurus-Hydra Supercluster Region. II.. The Astronomical Journal, 93, 1338. doi:10.1086/114416
• Costa, L. N., Maia, M. A., Pellegrini, P. S., Rite, C., & Willmer, C. N. (1987). New southern galaxies with active nuclei. The Astronomical Journal, 93, 546. doi:10.1086/114336
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  A list of AGN candidates, identified from optical spectra taken as part of an ongoing redshift survey of southern galaxies, is presented. The identification, coordinates, morphological type, measured heliocentric radial velocity, and proposed emission type are given for the galaxies showing evidence of nonstellar nuclear activity. Using standard diagnostics, several new Seyferts and low-ionization nuclear-emission regions (LINERs) are identified among the emission-line galaxies observed. 14 references.
• Chincarini, G., Costa, L. N., Cowan, J. J., Numes, M. A., Pellegrini, P. S., & Willmer, C. N. (1986). Redshift observations in the Centaurus-Hydra supercluster region. I. The Astronomical Journal, 91, 6-12. doi:10.1086/113974
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  In this paper we present 111 new redshifts in the region of the Centaurus-Hydra supercluster.
• Costa, L. N., Latham, D. W., Nunes, M. A., Pellegrini, P. S., & Willmer, C. N. (1984). Redshifts for 228 southern galaxies.. The Astronomical Journal, 89, 1310-1318. doi:10.1086/113629

Proceedings Publications

• Girard, J. H., Leisenring, J., Kammerer, J., Gennaro, M., Rieke, M., Stansberry, J., Rest, A., Egami, E., Sunnquist, B., Boyer, M., Canipe, A., Correnti, M., Hilbert, B., Perrin, M. D., Pueyo, L., Soummer, R., Allen, M., Bushouse, H., Aguilar, J., , Brooks, B., et al. (2022). JWST/NIRCam Coronagraphy: Commissioning and First On-Sky Results. In Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave, 12180.
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  In a cold and stable space environment, the James Webb Space Telescope (JWST or”Webb”) reaches unprecedented sensitivities at wavelengths beyond 2 microns, serving most fields of astrophysics. It also extends the parameter space of high-contrast imaging into the near and mid-infrared. Launched in late 2021, JWST underwent a six month commissioning period. In this contribution we focus on the NIRCam Coronagraphy mode which was declared”science ready” on July 10 2022, the last of the 17 JWST observing modes. Essentially, this mode enables the detection of fainter/redder/colder (less massive for a given age) self-luminous exoplanets as well as other faint astrophysical signal in the vicinity of any bright object (stars or galaxies). Here we describe some of the steps and hurdles the commissioning team went through to achieve excellent performance. Specifically, we focus on the Coronagraphic Suppression Verification activity. We were able to produce firm detections at 3.35µm of the white dwarf companion HD 114174 B which is at a separation of ' 0.500and a contrast of ' 10 magnitudes (104 fainter than the K∼5.3 mag host star). We compare these first on-sky images with our latest, most informed and realistic end-to-end simulations through the same pipeline. Additionally we provide information on how we succeeded with the target acquisition with all five NIRCam focal plane masks and their four corresponding wedged Lyot stops.
• Jansen}, R., Grogin, N., Windhorst, R., Ashcraft, T., Brisken, W., Cohen, S., Conselice, C., Driver, S., Finkelstein, S., Frye, B., Hathi, N., Jones, V., Joshi, B., Kim, D., Koekemoer, A., Maksym, W., Riess, A., Rodney, S., Royle, P., , Ryan, R., et al. (2020, jan). "UV-Visible observations with HST in the JWST North Ecliptic Pole Time-Domain Field". In American Astronomical Society Meeting Abstracts #235, 235.
• Willmer}, C. N., Hainline, K. N., Curtis-Lake, E., & Team, {. (2020, jan). "Guitarra, a Simulator for the JWST/NIRCam". In Uncovering Early Galaxy Evolution in the ALMA and JWST Era, 352.
• Jansen, R. A., Grogin, N., Ashcraft, T., Brisken, W., Cohen, S., Conselice, C., Driver, S., Finkelstein, S., Frye, B., Hathi, N., Jones, V., Joshi, B., Kim, D., Koekemoer, A., Maksym, W., Riess, A., Rodney, S., Royle, P., Ryan, R., , Smith, B., et al. (2019, jan). UV-Visible observations with HST in the JWST North Ecliptic Pole Time-Domain Field. In American Astronomical Society Meeting Abstracts #233, 233.
• Tyburczy, T., Jansen, R. A., Windhorst, R. A., Ashcraft, T., Cotton, W. D., Willmer, C., Grogin, N. A., & White, C. (2019, jun). Searching for Low-mass Stellar and Sub-stellar objects in the JWST North Ecliptic Pole Time-Domain Field. In American Astronomical Society Meeting Abstracts #234, 234.
• White, C. W., Jones, V., Jansen, R. A., Windhorst, R., Cohen, S., Willmer, C., & Hasinger, G. (2019, jan). Color-Selected AGN and Variable Objects in the JWST North Ecliptic Pole Time-Domain Field. In American Astronomical Society Meeting Abstracts #233, 233.
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