Peter A Milne

Interests

Research

UV, NIR, Optical and Gamma-ray Observations of type Ia Supernovae, Cosmology with type Ia Supernovae, robotic operation of telescopes and data pipelines.

Teaching

Introductory Astronomy, Cosmology, fully-online courses.

Courses

Scholarly Contributions

Journals/Publications

• , A. R., , W. F., , P. V., , T. L., , A. L., , K. P., , M. L., , P. K., , A. E., , N. R., , D. C., , E. B., , E. B., , B. C., , B. E., , A. C., , A. G., , R. M., , B. M., , , P. M., et al. (2021). GRB 180418A: A possibly-short GRB with a wide-angle outflow in a faint host galaxy.
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  We present X-ray and multi-band optical observations of the afterglow andhost galaxy of GRB 180418A, discovered by ${\it Swift}$/BAT and ${\itFermi}$/GBM. We present a reanalysis of the GBM and BAT data deriving durationsof the prompt emission of $T_{90}\approx$2.56s and $\approx$1.90s,respectively. Modeling the ${\it Fermi}$/GBM catalog of 1405 bursts (2008-2014)in the Hardness-$T_{90}$ plane, we obtain a probability of $\approx$60% thatGRB 180418A is a short-hard burst. From a combination of ${\it Swift}$/XRT and${\it Chandra}$ observations, the X-ray afterglow is detected to $\approx$38.5days after the burst, and exhibits a single power-law decline with $F_{\rm X}\propto t^{-0.98}$. Late-time Gemini observations reveal a faintr$\approx$25.69 mag host galaxy at an angular offset of $\approx$0.16''. At thelikely redshift range of z$\approx$1-2.25, we find that the X-ray afterglowluminosity of GRB 180418A is intermediate between short and long GRBs at allepochs during which there is contemporaneous data, and that GRB 180418A liescloser to the $E_{\gamma,{\rm peak}}-E_{\gamma,{\rm iso}}$ correlation forshort GRBs. Modeling the multi-wavelength afterglow with the standardsynchrotron model, we derive the burst explosion properties and find a jetopening angle of $\theta_{\rm j} \gtrsim 9-14^{\circ}$. If GRB 180418A is ashort GRB that originated from a neutron star merger, it has one of thebrightest and longest-lived afterglows along with an extremely faint hostgalaxy. If instead the event is a long GRB that originated from a massive starcollapse, it has among the lowest luminosity afterglows, and lies in a peculiarspace in terms of the Hardness-$T_{90}$ and $E_{\gamma,{\rmpeak}}-E_{\gamma,{\rm iso}}$ planes.[Journal_ref: ]
• , J. P., , J. B., , C. M., , P. A., & , J. E. (2021). The Hubble Constant from Infrared Surface Brightness Fluctuation Distances.
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  We present a measurement of the Hubble constant $H_0$ from surface brightnessfluctuation (SBF) distances for 63 bright, mainly early-type galaxies out to100 Mpc observed with the Wide Field Camera 3 Infrared Channel (WFC3/IR) on theHubble Space Telescope (HST). The sample is drawn from several independent HSTimaging programs using the F110W bandpass of WFC3/IR. The majority of galaxiesare in the 50 to 80 Mpc range and come from the MASSIVE galaxy survey. Themedian statistical uncertainty on individual distance measurements is 4%. Weconstruct the Hubble diagram with these IR SBF distances and constrain $H_0$using {four} different treatments of the galaxy velocities. For the SBF zeropoint calibration, we use both the existing tie to Cepheid variables, updatedfor consistency with the latest determination of the distance to the LargeMagellanic Cloud from detached eclipsing binaries, and a new tie to the tip ofthe red giant branch (TRGB) calibrated from the maser distance to NGC4258.These two SBF calibrations are consistent with each other and with theoreticalpredictions from stellar population models. From a weighted average of theCepheid and TRGB calibrations, we derive $H_0=73.3{\,\pm\,}0.7{\,\pm\,}2.4$km/s/Mpc, where the error bars reflect the statistical and systematicuncertainties. This result accords well with recent measurements of $H_0$ fromType~Ia supernovae, time delays in multiply lensed quasars, and water masers.The systematic uncertainty could be reduced to below 2% by calibrating the SBFmethod with precision TRGB distances for a statistical sample of massiveearly-type galaxies out to the Virgo cluster measured with the James Webb SpaceTelescope.[Journal_ref: ]
• , N. S., , J. E., , J. C., , W. Z., , A. V., , M. L., & , P. M. (2021). The Persistent Eruption of UGC~2773-OT: Finally, a Decade-Long Extragalactic Eta Carinae Analog.
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  While SN impostors resemble the Great Eruption of eta Car in the sense thattheir spectra show narrow H lines and they have typical peak absolutemagnitudes of -13 to -14 mag, most extragalactic events observed so far arequite different from eta Car in duration. Their bright phases typically lastfor 100~d or less, rather than persisting for several years. The transientobject UGC2773-OT had a similar peak absolute magnitude to other SN impostors,but with a gradual 5-yr prediscovery rise. In the 6 yr since discovery, it hasfaded very slowly (0.26 mag/yr). Overall, we suggest that its decade-longeruption is so far the best known analog of eta Car's 19th century eruption. Wediscuss extensive spectroscopy of the ongoing eruption. The spectra showinteresting changes in velocity and line shape that we discuss in detail,including an asymmetric Halpha emission line that we show is consistent withthe ejection of a bipolar nebula that could be very much like the Homunculus ofeta Car. Moreover, changes in the line width, line profile, blue excessemission resembling that of Type IIn supernovae, and the intensity of Halphasuggest the presence of strong circumstellar interaction in the eruption atlate times. This supports the hypothesis that the extended plateau of eta Car'seruption may have been powered by shock interaction as well. One interestingdifference compared to eta Car, however, is that UGC2773-OT so far does notexhibit the repeated brief spikes in luminosity that have been associated withbinary periastron events.[Journal_ref: ]
• , N. S., , J. E., , M. M., , P. M., , C. B., , C. D., , W. F., , C. B., , A. V., , M. K., & , J. M. (2021). A new and unusual LBV-like outburst from a Wolf-Rayet star in the outskirts of M33.
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  MCA-1B (also called UIT003) is a luminous hot star in the western outskirtsof M33, classified over 20yr ago with a spectral type of Ofpe/WN9 andidentified then as a candidate luminous blue variable (LBV). Palomar TransientFactory data reveal that this star brightened in 2010, with a light curveresembling that of the classic LBV star AFAnd in M31. Other Ofpe/WN9 stars haveerupted as LBVs, but MCA-1B was unusual because it remained hot. It showed aWN-type spectrum throughout its eruption, whereas LBVs usually get much cooler.MCA-1B showed an almost four-fold increase in bolometric luminosity and adoubling of its radius, but its temperature stayed around 29kK. As it faded, itshifted to even hotter temperatures, exhibiting a WN7/WN8-type spectrum, anddoubling its wind speed. MCA-1B is reminiscent of some supernova impostors, andits location resembles the isolated environment of SN 2009ip. It is mostsimilar to HD5980 (in the SMC) and GR 290 (also in M33). Whereas these two LBVsexhibited B-type spectra in eruption, MCA-1B is the first clear case where aWolf-Rayet (WR) spectrum persisted at all times. Together, MCA-1B, HD 5980, andGR 290 constitute a class of WN-type LBVs, distinct from S Doradus LBVs. Theyare most interesting in the context of LBVs at low metallicity, a possiblepost-LBV/WR transition in binaries, and as likely Type~Ibn supernovaprogenitors.[Journal_ref: ]
• Milne, P. A. (2021). Infrared Surface Brightness Fluctuation Distances for MASSIVE and Type Ia Supernova Host Galaxies. The Astrophysical Journal Supplement Series, 255(2), 17.
• , C. D., , J. E., , N. S., , P. M., , G. H., , W. Z., & , A. V. (2020). An Optical and Near-Infrared Study of the Type Ia/IIn Supernova PS15si.
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  We present optical/near-infrared spectroscopy and photometry of the supernova(SN) PS15si. This object was originally identified as a Type IIn SN, but herewe argue that it should be reclassified as a Type Ia SN with narrow hydrogenlines originating from interaction with circumstellar matter (CSM; i.e., SNIa/IIn or SN Ia-CSM). Based on deep nondetections 27 days before discovery, weinfer that this SN was discovered around or slightly before optical maximum,and we estimate the approximate time that it reached R-band maximum based oncomparison with other SNe Ia/IIn. In terms of spectral morphology, we find thatPS15si can be matched to a range of SN Ia spectral types, although SN1991T-like SNe Ia provides the most self-consistent match. While thisobservation agrees with analysis of most other SNe Ia/IIn, we find that theimplied CSM luminosity is too low to account for the overall luminosity of theSN at a time when the CSM should outshine the underlying SN by a fewmagnitudes. We infer that the similarity between PS15si and the hot,overluminous, high-ionisation spectrum of SN 1991T is a consequence of aspectrum that originates in ejecta layers that are heated by ultraviolet/X-rayradiation from CSM interaction. In addition, PS15si may have rebrightened overa short timescale in the B and V bands around 85 days after discovery, perhapsindicating that the SN ejecta are interacting with a local enhancement in CSMproduced by clumps or a shell at large radii.[Journal_ref: ]
• , C. P., , D. A., , S. K., , J. B., , D. H., , C. M., , P. A., , J. E., , P. B., , L. C., , E. Y., , D. J., , M. S., , N. S., , S. V., , J. V., , J. C., , S. W., & , Y. Y. (2020). Constraining the Source of the High-velocity Ejecta in Type Ia SN 2019ein. The Astrophysical Journal, Volume, 159-176.
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  We present multiwavelength photometric and spectroscopic observations of SN2019ein, a high-velocity Type Ia supernova (SN Ia) discovered in the nearbygalaxy NGC 5353 with a two-day nondetection limit. SN 2019ein exhibited some ofthe highest measured expansion velocities of any SN Ia, with a Si II absorptionminimum blueshifted by 24,000 km s$^{-1}$ at 14 days before peak brightness.More unusually, we observed the emission components of the P Cygni profiles tobe blueshifted upward of 10,000 km s$^{-1}$ before B-band maximum light. Thisblueshift, among the highest in a sample of 28 other Type Ia supernovae, isgreatest at our earliest spectroscopic epoch and subsequently decreases towardmaximum light. We discuss possible progenitor systems and explosion mechanismsthat could explain these extreme absorption and emission velocities. Radioobservations beginning 14 days before B-band maximum light yield nondetectionsat the position of SN 2019ein, which rules out symbiotic progenitor systems,most models of fast optically thick accretion winds, and optically thin shellsof mass $\lesssim 10^{-6}$ M$_\odot$ at radii $< 100$ AU. Comparing our spectrato models and observations of other high-velocity SNe Ia, we find that SN2019ein is well fit by a delayed-detonation explosion. We propose that the highemission velocities may be the result of abundance enhancements due to ejectamixing in an asymmetric explosion, or optical depth effects in the photosphereof the ejecta at early times. These findings may provide evidence for commonexplosion mechanisms and ejecta geometries among high-velocity SNe Ia.[Journal_ref: The Astrophysical Journal, Volume 897, Number 2, pp. 159-176, 2020]
• , K. A., , S. V., , D. J., , J. E., , S. D., , L. G., , D. P., , R. C., , N. S., , S. Y., , G. C., , I. A., , E. B., , P. J., , J. B., , R. C., , D. H., , Y. D., , E. E., , , S. E., et al. (2020). Discovery and Rapid Follow-up Observations of the Unusual Type II SN 2018ivc in NGC 1068. The Astrophysical Journal,.
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  We present the discovery and high-cadence follow-up observations of SN2018ivc, an unusual Type II supernova that exploded in NGC 1068 (D=10.1 Mpc).The light curve of SN 2018ivc declines piecewise-linearly, changing slopefrequently, with four clear slope changes in the first 30 days of evolution.This rapidly changing light curve indicates that interaction between thecircumstellar material and ejecta plays a significant role in the evolution.Circumstellar interaction is further supported by a strong X-ray detection. Thespectra are rapidly evolving and dominated by hydrogen, helium, and calciumemission lines. We identify a rare high-velocity emission-line featureblueshifted at ~7800 km/s (in Ha, Hb, Pb, Pg, HeI, CaII), which is visible fromday 18 until at least day 78 and could be evidence of an asymmetric progenitoror explosion. From the overall similarity between SN 2018ivc and SN 1996al, the\Ha{} equivalent width of its parent HII region, and constraints frompre-explosion archival Hubble Space Telescope images, we find that theprogenitor of SN 2018ivc could be as massive as 52 Msun but is more likely
• , P. J., , E. B., , P. M., , P. W., & , L. W. (2020). Theoretical Clues to the Ultraviolet Diversity of Type Ia Supernovae.
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  The effect of metallicity on the observed light of Type Ia supernovae (SNeIa) could lead to systematic errors as the absolute magnitudes of local anddistant SNe Ia are compared to measure luminosity distances and determinecosmological parameters. The UV light may be especially sensitive tometallicity, though different modeling methods disagree as to the magnitude,wavelength dependence, and even the sign of the effect. The outer densitystructure, ^56 Ni, and to a lesser degree asphericity, also impact the UV. Wecompute synthetic photometry of various metallicity-dependent models andcompare to UV/optical photometry from the Swift Ultra-Violet/Optical Telescope.We find that the scatter in the mid-UV to near-UV colors is larger thanpredicted by changes in metallicity alone and is not consistent with reddening.We demonstrate that a recently employed method to determine relative abundancesusing UV spectra can be done using UVOT photometry, but we warn that accurateresults require an accurate model of the cause of the variations. The abundanceof UV photometry now available should provide constraints on models thattypically rely on UV spectroscopy for constraining metallicity, density, andother parameters. Nevertheless, UV spectroscopy for a variety of SN explosionsis still needed to guide the creation of accurate models. A betterunderstanding of the influences affecting the UV is important for using SNe Iaas cosmological probes, as the UV light may test whether SNe Ia aresignificantly affected by evolutionary effects.[Journal_ref: ]
• , R. J., , S. L., , L. M., , A. G., , P. J., , A. V., , M. L., & , P. A. (2020). Significant Luminosity Differences of Two Twin Type Ia Supernovae.
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  The Type Ia supernovae (SNe Ia) 2011by, hosted in NGC 3972, and 2011fe,hosted in M101, are optical "twins," having almost identical opticallight-curve shapes, colours, and near-maximum-brightness spectra. However, SN2011fe had significantly more ultraviolet (UV; 1600 < lambda < 2500 A) fluxthan SN 2011by before and at peak luminosity. Theory suggests that SNe Ia withhigher progenitor metallicity should (1) have additional UV opacity near peakand thus lower UV flux; (2) have an essentially unchanged opticalspectral-energy distribution; (3) have a similar optical light-curve shape; and(4) because of the excess neutrons, produce more stable Fe-group elements atthe expense of radioactive 56Ni and thus have a lower peak luminosity. Foley &Kirshner (2013) suggested that the difference in UV flux between SNe 2011by and2011fe was the result of their progenitors having significantly differentmetallicities. The SNe also had a large, but insignificant, difference betweentheir peak absolute magnitudes (Delta M_V, peak = 0.60 +/- 0.36 mag), with SN2011fe being more luminous. We present a new Cepheid-based distance to NGC3972, significantly improving the precision of the distance measurement for SN2011by. With these new data, we determine that the SNe have significantlydifferent peak luminosities (Delta M_V, peak = 0.335 +/- 0.069 mag),corresponding to SN 2011fe having produced 38% more 56Ni than SN 2011by, andproviding additional evidence for progenitor metallicity differences for theseSNe. We discuss how progenitor metallicity differences can contribute to theintrinsic scatter for light-curve-shape-corrected SN luminosities, the use of"twin" SNe for measuring distances, and implications for using SNe Ia forconstraining cosmological parameters.[Journal_ref: ]
• Milne, P. A. (2020). SN 2014ab: An Aspherical Type IIn Supernova with Low Polarization. MNRAS.
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  We present photometry, spectra, and spectropolarimetry of supernova (SN)2014ab, obtained through $\sim 200$ days after peak brightness. SN 2014ab was aluminous Type IIn SN ($M_V < -19.14$ mag) discovered after peak brightness nearthe nucleus of its host galaxy, VV 306c. Prediscovery upper limits constrainthe time of explosion to within 200 days prior to discovery. While SN 2014abdeclined by $\sim 1$ mag over the course of our observations, the observedspectrum remained remarkably unchanged. Spectra exhibit an asymmetricemission-line profile with a consistently stronger blueshifted component,suggesting the presence of dust or a lack of symmetry between the far side andnear side of the SN. The Pa$\beta$ emission line shows a profile very similarto that of H$\alpha$, implying that this stronger blueshifted component iscaused either through obscuration by large dust grains, occultation byoptically thick material, or a lack of symmetry between the far side and nearside of the interaction region. Despite these asymmetric line profiles, ourspectropolarimetric data show that SN 2014ab has little detected polarizationafter accounting for the interstellar polarization. This suggests that we areseeing emission from a photosphere that has only small deviation from circularsymmetry face-on. We are likely seeing a SN IIn with nearly circular symmetryin the plane normal to our line of sight, but with either large-grain dust orsignificant asymmetry in the density of circumstellar material or SN ejectaalong our line of sight. We suggest that SN 2014ab and SN 2010jl (as well asother SNe IIn) may be similar events viewed from different directions.[Journal_ref: ]
• , C. L., , F. T., , A. L., , A. C., , F. A., , W. A., , A. A., , D. A., , K. A., , M. A., , C. B., , E. B., , A. B., , J. B., , J. B., , S. B., , P. B., , S. B., , A. B., , , T. B., et al. (2019). Catching Element Formation In The Act.
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  Gamma-ray astronomy explores the most energetic photons in nature to addresssome of the most pressing puzzles in contemporary astrophysics. It encompassesa wide range of objects and phenomena: stars, supernovae, novae, neutron stars,stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic raysand relativistic-particle acceleration, and the evolution of galaxies. MeVgamma-rays provide a unique probe of nuclear processes in astronomy, directlymeasuring radioactive decay, nuclear de-excitation, and positron annihilation.The substantial information carried by gamma-ray photons allows us to seedeeper into these objects, the bulk of the power is often emitted at gamma-rayenergies, and radioactivity provides a natural physical clock that adds uniqueinformation. New science will be driven by time-domain population studies atgamma-ray energies. This science is enabled by next-generation gamma-rayinstruments with one to two orders of magnitude better sensitivity, larger skycoverage, and faster cadence than all previous gamma-ray instruments. Thistransformative capability permits: (a) the accurate identification of thegamma-ray emitting objects and correlations with observations taken at otherwavelengths and with other messengers; (b) construction of new gamma-ray mapsof the Milky Way and other nearby galaxies where extended regions aredistinguished from point sources; and (c) considerable serendipitous science ofscarce events -- nearby neutron star mergers, for example. Advances intechnology push the performance of new gamma-ray instruments to address a wideset of astrophysical questions.[Journal_ref: ]
• , D. J., , R. C., , M. M., , M. L., , J. E., , J. B., , R. C., , Y. E., , L. G., , D. H., , D. A., , S. W., , M. L., , T. M., , C. M., , P. M., , N. S., , S. V., & , S. W. (2019). Nebular H$α$ Limits for Fast Declining Type Ia Supernovae.
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  One clear observational prediction of the single degenerate progenitorscenario as the origin of type Ia supernovae (SNe) is the presence ofrelatively narrow ($\approx$1000 km s$^{-1}$) H$\alpha$ emission at nebularphases, although this feature is rarely seen. We present a compilation ofnebular phase H$\alpha$ limits for SN Ia in the literature and demonstrate thatthis heterogenous sample has been biased towards SN Ia with relatively highluminosities and slow decline rates, as parameterized by $\Delta$m$_{15}(B)$,the difference in $B$-band magnitude between maximum light and fifteen daysafterward. Motivated by the need to explore the full parameter space of SN~Iaand their subtypes, we present two new and six previously published nebularspectra of SN Ia with $\Delta$m$_{15}(B)$$ > $1.3 mag (including members of thetransitional and SN1991bg-like subclasses) and measure nondetection limits of$L_{H\alpha}$$~
• , J. E., , D. J., , S. V., , N. S., , R. D., , D. K., , K. M., , A. S., , D. H., , P. J., , G. H., , S. W., , J. V., , G. C., , I. A., , C. A., , S. B., , M. B., , K. A., , , M. B., et al. (2019). SN 2017gmr: An energetic Type II-P supernova with asymmetries.
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  We present high-cadence ultraviolet (UV), optical, and near-infrared (NIR)data on the luminous Type II-P supernova SN 2017gmr from hours after discoverythrough the first 180 days. SN 2017gmr does not show signs of narrow,high-ionization emission lines in the early optical spectra, yet the opticallightcurve evolution suggests that an extra energy source from circumstellarmedium (CSM) interaction must be present for at least 2 days after explosion.Modeling of the early lightcurve indicates a ~500R$_{\odot}$ progenitor radius,consistent with a rather compact red supergiant, and late-time luminositiesindicate up to 0.130 $\pm$ 0.026 M$_{\odot}$ of $^{56}$Ni are present, if thelightcurve is solely powered by radioactive decay, although the $^{56}$Ni massmay be lower if CSM interaction contributes to the post-plateau luminosity.Prominent multi-peaked emission lines of H$\alpha$ and [O I] emerge after day154, as a result of either an asymmetric explosion or asymmetries in the CSM.The lack of narrow lines within the first two days of explosion in the likelypresence of CSM interaction may be an example of close, dense, asymmetric CSMthat is quickly enveloped by the spherical supernova ejecta.[Journal_ref: ]
• , M. J., , K. P., , W. F., , D. J., , J. E., , I. S., , P. N., , S. V., , S. Y., , E. C., , A. R., , F. S., , S. W., , O. K., , R. C., , I. A., , P. B., , N. B., , L. C., , , A. C., et al. (2019). Searches After Gravitational-waves Using ARizona Observatories (SAGUARO): System Overview and First Results from Advanced LIGO/Virgo's Third Observing Run.
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  We present Searches After Gravitational-waves Using ARizona Observatories(SAGUARO), a comprehensive effort dedicated to the discovery andcharacterization of optical counterparts to gravitational wave (GW) events.SAGUARO utilizes ground-based facilities ranging from 1.5m to 10m in diameter,located primarily in the Northern Hemisphere. We provide an overview ofSAGUARO's telescopic resources, pipeline for transient detection, and databasefor candidate visualization. We describe SAGUARO's discovery component, whichutilizes the $5$~deg$^2$ field-of-view optical imager on the Mt. Lemmon 1.5mtelescope, reaching limits of $\approx 21.3$~AB mag while rapidly tiling largeareas. We also describe the follow-up component of SAGUARO, used for rapidvetting and monitoring of optical candidates. With the onset of AdvancedLIGO/Virgo's third observing run, we present results from the first threeSAGUARO searches following the GW events S190408an, S190425z and S190426c,which serve as a valuable proof-of-concept of SAGUARO. We triggered andsearched 15, 60 and 60 deg$^{2}$ respectively, 17.6, 1.4 and 41.8 hrs after theinitial GW alerts. We covered 7.8, 3.0 and 5.1\% of the total probabilitywithin the GW event localizations, reaching 3$\sigma$ limits of 19.8, 21.3 and20.8 AB mag, respectively. Although no viable counterparts associated withthese events were found, we recovered 6 known transients and ruled out 5potential candidates. We also present Large Binocular Telescope spectroscopy ofPS19eq/SN2019ebq, a promising kilonova candidate that was later determined tobe a supernova. With the ability to tile large areas and conduct detailedfollow-up, SAGUARO represents a significant addition to GW counterpartsearches.[Journal_ref: ]
• , P. C., , S. D., , B. K., , C. S., , J. A., , K. M., , M. M., , J. L., , B. J., , M. D., , S. B., , P. J., , T. W., , L. G., , P. A., , N. M., , A. L., , K. Z., , T. A., & , D. R. (2019). ASASSN-15pz: Revealing Significant Photometric Diversity among 2009dc-like, Peculiar SNe Ia.
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  We report comprehensive multi-wavelength observations of a peculiar TypeIa-like supernova ("SN Ia-pec") ASASSN-15pz. ASASSN-15pz is a spectroscopic"twin" of SN 2009dc, a so-called "Super-Chandrasekhar-mass" SN, throughout itsevolution, but it has a peak luminosity M_B,peak = -19.69 +/- 0.12 mag that is\approx 0.6 mag dimmer and comparable to the SN 1991T sub-class of SNe Ia atthe luminous end of the normal width-luminosity relation. The synthesized Ni56mass of M_Ni56 = 1.13 +/- 0.14 M_sun is also substantially less than that foundfor several 2009dc-like SNe. Previous well-studied 2009dc-like SNe havegenerally suffered from large and uncertain amounts of host-galaxy extinction,which is negligible for ASASSN-15pz. Based on the color of ASASSN-15pz, weestimate a host extinction for SN 2009dc of E(B-V)_host=0.12 mag and confirmits high luminosity (M_B, peak[2009dc] \approx -20.3 mag). The 2009dc-like SNpopulation, which represents ~1% of SNe Ia, exhibits a range of peakluminosities, and do not fit onto the tight width-luminosity relation. Theiroptical light curves also show significant diversity of late-time (>~ 50 days)decline rates. The nebular-phase spectra provide powerful diagnostics toidentify the 2009dc-like events as a distinct class of SNe Ia. We suggestreferring to these sources using the phenomenology-based "2009dc-like SNIa-pec" instead of "Super-Chandrasekhar SN Ia," which is based on an uncertaintheoretical interpretation.[Journal_ref: ]
• , R. S., , M. A., , J. F., , P. F., , A. B., , C. L., , J. O., , D. H., , P. H., , A. H., , D. J., , M. D., , P. M., , P. N., , F. S., , T. S., , L. -., , Z. Y., & , C. A. (2019). Ex Luna, Scientia: The Lunar Occultation eXplorer (LOX).
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  LOX is a lunar-orbiting astrophysics mission that will probe the cosmos atMeV energies. It is guided by open questions regarding thermonuclear, orType-Ia, supernovae (SNeIa) and will characterize these inherently radioactiveobjects by enabling a systematic survey of SNeIa at gamma-ray energies for thefirst time. Astronomical investigations from lunar orbit afford newopportunities to advance our understanding of the cosmos. The foundation of LOXis an observational approach well suited to the all-sky monitoring demands ofsupernova investigations and time-domain astronomy. Its inherently widefield-of-view and continuous all-sky monitoring provides an innovative way ofaddressing decadal survey questions at MeV energies (0.1-10 MeV). The LOXapproach achieves high sensitivity with a simple, high-heritage instrumentdesign that eliminates the need for complex, position-sensitive detectors,kinematic event reconstruction, masks, or other insensitive detector mass,while also mitigating technology development, implementation complexity, andtheir associated costs. LOX can be realized within existing programs, likeExplorer.[Journal_ref: ]
• , W. L., , X. W., , J. V., , J. M., , G. H., , D. J., , J. Z., , H. L., , T. Z., , L. W., , Z. C., , D. X., , L. R., , F. H., , X. L., , X. Z., , L. L., , E. B., , J. M., , , X. Z., et al. (2019). Photometric and Spectroscopic Properties of Type Ia Supernova 2018oh with Early Excess Emission from the $Kepler$ 2 Observations.
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  Supernova (SN) 2018oh (ASASSN-18bt) is the first spectroscopically-confirmedtype Ia supernova (SN Ia) observed in the $Kepler$ field. The $Kepler$ datarevealed an excess emission in its early light curve, allowing to placeinteresting constraints on its progenitor system (Dimitriadis et al. 2018,Shappee et al. 2018b). Here, we present extensive optical, ultraviolet, andnear-infrared photometry, as well as dense sampling of optical spectra, forthis object. SN 2018oh is relatively normal in its photometric evolution, witha rise time of 18.3$\pm$0.3 days and $\Delta$m$_{15}(B)=0.96\pm$0.03 mag, butit seems to have bluer $B - V$ colors. We construct the "uvoir" bolometriclight curve having peak luminosity as 1.49$\times$10$^{43}$erg s$^{-1}$, fromwhich we derive a nickel mass as 0.55$\pm$0.04M$_{\odot}$ by fitting radiationdiffusion models powered by centrally located $^{56}$Ni. Note that the momentwhen nickel-powered luminosity starts to emerge is +3.85 days after the firstlight in the Kepler data, suggesting other origins of the early-time emission,e.g., mixing of $^{56}$Ni to outer layers of the ejecta or interaction betweenthe ejecta and nearby circumstellar material or a non-degenerate companionstar. The spectral evolution of SN 2018oh is similar to that of a normal SN Ia,but is characterized by prominent and persistent carbon absorption features.The C II features can be detected from the early phases to about 3 weeks afterthe maximum light, representing the latest detection of carbon ever recorded ina SN Ia. This indicates that a considerable amount of unburned carbon exists inthe ejecta of SN 2018oh and may mix into deeper layers.[Journal_ref: ]
• , C. B., , N. S., , G. G., , J. C., , J. E., , W. F., , C. B., , C. D., , P. A., , O. D., , S. B., , A. V., , W. Z., , P. L., & , K. I. (2018). SN2013fs and SN2013fr: Exploring the circumstellar-material diversity in Type II supernovae.
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  We present photometry and spectroscopy of SN2013fs and SN2013fr in the first100 days post-explosion. Both objects showed transient, relatively narrowH$\alpha$ emission lines characteristic of SNeIIn, but later resembled normalSNeII-P or SNeII-L, indicative of fleeting interaction with circumstellarmaterial (CSM). SN2013fs was discovered within 8hr of explosion. Its lightcurve exhibits a plateau, with spectra revealing strong CSM interaction atearly times. It is a less luminous version of the transitional SNIIn PTF11iqb,further demonstrating a continuum of CSM interaction intensity between SNeII-Pand IIn. It requires dense CSM within 6.5$\times$10$^{14}$~cm of theprogenitor, from a phase of advanced pre-SN mass loss shortly before explosion.Spectropolarimetry of SN2013fs shows little continuum polarization, butnoticeable line polarization during the plateau phase. SN2013fr morphed from aSNIIn at early times to a SNII-L. After the first epoch its narrow linesprobably arose from host-galaxy emission, but the bright, narrow H$\alpha$emission at early times may be intrinsic. As for SN2013fs, this would point toa short-lived phase of strong CSM interaction if proven to be intrinsic,suggesting a continuum between SNeIIn and II-L. It is a low-velocity SNII-L,like SN2009kr but more luminous. SN2013fr also developed an IR excess at latertimes, due to warm CSM dust that require a more sustained phase of strongpre-SN mass loss.[Journal_ref: ]
• , C. B., , N. S., , G. G., , P. S., , W. Z., , M. L., , J. C., , J. E., , A. V., , C. A., , E. C., , J. L., , L. H., , D. C., , G. H., , P. M., , R. M., , J. M., , J. V., , , J. C., et al. (2018). SN2012ab: A Peculiar Type IIn Supernova with Aspherical Circumstellar Material.
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  We present photometry, spectra, and spectropolarimetry of supernova (SN)2012ab, mostly obtained over the course of $\sim 300$ days after discovery. SN2012ab was a Type IIn (SN IIn) event discovered near the nucleus of spiralgalaxy 2MASXJ12224762+0536247. While its light curve resembles that of SN1998S, its spectral evolution does not. We see indications of CSM interactionin the strong intermediate-width emission features, the high luminosity (peakat absolute magnitude $M=-19.5$), and the lack of broad absorption features inthe spectrum. The H$\alpha$ emission undergoes a peculiar transition. At earlytimes it shows a broad blue emission wing out to $-14{,}000$ km$\mathrm{s^{-1}}$ and a truncated red wing. Then at late times ($>$100$\,$days) it shows a truncated blue wing and a very broad red emission wingout to roughly $+20{,}000$ km $\mathrm{s^{-1}}$. This late-time broad red wingprobably arises in the reverse shock. Spectra also show an asymmetricintermediate-width H$\alpha$ component with stronger emission on the red sideat late times. The evolution of the asymmetric profiles requires a densitystructure in the distant CSM that is highly aspherical. Our spectropolarimetricdata also suggest asphericity with a strong continuum polarization of $\sim1-3$% and depolarization in the H$\alpha$ line, indicating asphericity in theCSM at a level comparable to that in other SNe IIn. We estimate a mass-lossrate of $\dot{M} = 0.050\, {\rm M}_{\odot}\,\mathrm{yr^{-1}}$ for $v_{\rm pre}= 100$$\,$km$\,$$\mathrm{s^{-1}}$ extending back at least 75$\,$yr prior to theSN. The strong departure from axisymmetry in the CSM of SN 2012ab may suggestthat the progenitor was an eccentric binary system undergoing eruptive massloss.[Journal_ref: ]
• , P. J., , J. M., , B. A., , P. A., & , X. W. (2018). The Ultraviolet Colors of Type Ia Supernovae and their Photospheric Velocities.
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  We compare ultraviolet (UV) and optical colors of a sample of 29 type Iasupernovae (SNe Ia) observed with the Swift satellite's UltraViolet OpticalTelescope (UVOT) with theoretical models of an asymmetric explosion viewed fromdifferent angles from Kasen & Plewa. This includes mid-UV (1600-2700 Angstroms;uvw2 and uvm2) and near-UV (2700-4000 Angstroms; uvw1 and u) filters. We findthe observed colors to be much redder than the model predictions, and thatthese offsets are unlikely to be caused by dust reddening. We confirm previousresults that high-velocity SNe Ia have red UV-optical colors. When correctingthe colors for dust reddening by assuming a constant b-v color we find nocorrelation between the uvw1-v or u-v colors and the ejecta velocities for 25SNe Ia with published velocities and/or spectra. When assuming an opticalcolor-velocity relation, a correlation of 2 and 3.6 sigma is found for uvw1-vand u-v. However, we find that the correlation is driven by the reddeningcorrection and can be reproduced with random colors which are corrected forreddening. The significance of a correlation between the UV colors and thevelocity is thus dependent on the assumed slope of the optical color-velocityrelation. After such a correction, the uvw1-v versus velocity slope isshallower than that predicted by the models and offset to redder colors. Asignificant scatter still remains in the uvw1-v colors including a large spreadat low velocities. This demonstrates that the NUV-blue/red spread is not causedsolely by the photospheric velocity. The uvm2-uvw1 colors also show a largedispersion which is uncorrelated with the velocity.[Journal_ref: ]
• , S. B., , S. D., , C. S., , A. P., , B. K., , D. B., , J. E., , J. L., , K. Z., , B. J., , N. S., , J. K., , S. B., , E. C., , P. C., , N. E., , P. M., , A. M., , L. T., , , L. T., et al. (2018). ASASSN-15nx: A luminous Type II supernova with a "perfect" linear decline.
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  We report a luminous Type II supernova, ASASSN-15nx, with a peak luminosityof M_V=-20 mag, that is between typical core-collapse supernovae andsuper-luminous supernovae. The post-peak optical light curves show a long,linear decline with a steep slope of 2.5 mag/100 days (i.e., an exponentialdecline in flux), through the end of observations at phase ~260 days. Incontrast, the light curves of hydrogen rich supernovae (SNe II-P/L) always showbreaks in their light curves at phase ~100 days, before settling onto Co56radioactive decay tails with a decline rate of about 1 mag/100 days. Thespectra of ASASSN-15nx do not exhibit the narrow emission-line featurescharacteristic of Type IIn SNe, which can have a wide variety of light-curveshapes usually attributed to strong interactions with a dense circumstellarmedium (CSM). ASASSN-15nx has a number of spectroscopic peculiarities,including a relatively weak and triangularly-shaped H-alpha emission profilewith no absorption component. The physical origin of these peculiarities isunclear, but the long and linear post-peak light curve without a break suggestsa single dominant powering mechanism. Decay of a large amount of Ni56 (M_Ni56 =1.6 +/- 0.2 M_sun) can power the light curve of ASASSN-15nx, and the steeplight-curve slope requires substantial gamma-ray escape from the ejecta, whichis possible given a low-mass hydrogen envelope for the progenitor. Anotherpossibility is strong CSM interactions powering the light curve, but the CSMneeds to be sculpted to produce the unique light-curve shape and to avoidproducing SN IIn-like narrow emission lines.[Journal_ref: ]
• , P. J., , N. J., , P. A., & , M. D. (2017). Reddened, Redshifted, or Intrinsically Red? Understanding Near-Ultraviolet Colors of Type Ia Supernovae.
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  Understanding the intrinsic colors of Type Ia supernovae (SNe Ia) isimportant to their use as cosmological standard candles. Understanding theeffects of reddening and redshift on the observed colors are complicated anddependent on the intrinsic spectrum, the filter curves, and the wavelengthdependence of reddening. We present ultraviolet and optical data of a growingsample of SNe Ia observed with the Ultra-Violet/Optical Telescope on the Swiftspacecraft and use this sample to re-examine the near-UV (NUV) colors of SNeIa. We find that a small amount of reddening (E(B-V)=0.2 mag) could account forthe difference between groups designated as NUV-blue and NUV-red, and amoderate amount of reddening (E(B-V)=0.5 mag) could account for the wholeNUV-optical differences. The reddening scenario, however, is inconsistent withthe mid-UV colors and color evolution. The effect of redshift alone onlyaccounts for part of the variation. Using a spectral template of SN2011fe wecan forward model the effects of redshift and reddening and directly comparewith the observed colors. We find that some SNe are consistent with reddenedversions of SN2011fe, but most SNe Ia are much redder in the uvw1-v color thanSN2011fe reddened to the same b-v color. The absolute magnitudes show that twoof five NUV-blue SNe Ia are blue because their near-UV luminosity is high, andthe other three are optically fainter. We also show that SN2011fe is not a"normal" SN Ia in the UV, but has colors placing it at the blue extreme of oursample.[Journal_ref: ]
• Milne, P. A. (2017). Multiepoch Spectropolarimetry of SN 2011fe. apj, 835(100), 11. doi:10.3847/1538-4357/835/1/100
• , A. L., , M. D., , G. G., , P. M., , P. S., , N. S., , C. B., , J. L., , L. H., & , D. C. (2016). Asymmetries in SN 2014J Near Maximum Light Revealed Through Spectropolarimetry.
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  We present spectropolarimetric observations of the nearby Type Ia SN 2014J inM82 over six epochs: +0, +7, +23, +51, +77, +109, and +111 days with respect toB-band maximum. The strong continuum polarization, which is constant with time,shows a wavelength dependence unlike that produced by linear dichroism in MilkyWay dust. The observed polarization may be due entirely to interstellar dust orinclude a circumstellar scattering component. We find that the polarizationangle aligns with the magnetic field of the host galaxy, arguing for aninterstellar origin. Additionally, we confirm a peak in polarization at shortwavelengths that would imply $R_V < 2 $ along the light of sight, in agreementwith earlier polarization measurements. For illustrative purposes, we include atwo component fit to the continuum polarization of our +51 day epoch thatcombines a circumstellar scattering component with interstellar dust wherescattering can account for over half of the polarization at $4000$ \AA. Uponremoval of the interstellar polarization signal, SN 2014J exhibits very lowlevels of continuum polarization. Asymmetries in the distribution of elementswithin the ejecta are visible through moderate levels of time-variablepolarization in accordance with the Si II 6355 \AA absorption line. At maximumlight, the line polarization reaches $\sim0.6$% and decreases to $\sim0.4\%$one week later. This feature also forms a loop on the $q_{RSP}$-$u_{RSP}$ planeillustrating that the ion does not have an axisymmetric distribution. Theobserved polarization properties suggest the explosion geometry of SN 2014J isgenerally spheroidal with a clumpy distribution of silicon.[Journal_ref: ]
• , R. J., , Y. P., , P. B., , A. V., , O. D., , W. H., , R. P., , G. H., , P. A., , J. T., , G. P., & , M. D. (2016). Ultraviolet Diversity of Type Ia Supernovae.
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  Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) probe theoutermost layers of the explosion, and UV spectra of SNe Ia are expected to beextremely sensitive to differences in progenitor composition and the details ofthe explosion. Here we present the first study of a sample of highsignal-to-noise ratio SN Ia spectra that extend blueward of 2900 A. We focus onspectra taken within 5 days of maximum brightness. Our sample of ten SNe Iaspans the majority of the parameter space of SN Ia optical diversity. We findthat SNe Ia have significantly more diversity in the UV than in the optical,with the spectral variance continuing to increase with decreasing wavelengthsuntil at least 1800 A (the limit of our data). The majority of the UV variancecorrelates with optical light-curve shape, while there are no obvious andunique correlations between spectral shape and either ejecta velocity orhost-galaxy morphology. Using light-curve shape as the primary variable, wecreate a UV spectral model for SNe Ia at peak brightness. With the model, wecan examine how individual SNe vary relative to expectations based on onlytheir light-curve shape. Doing this, we confirm an excess of flux for SN 2011feat short wavelengths, consistent with its progenitor having a subsolarmetallicity. While most other SNe Ia do not show large deviations from themodel, ASASSN-14lp has a deficit of flux at short wavelengths, suggesting thatits progenitor was relatively metal rich.[Journal_ref: ]
• Milne, P. A. (2016). The Persistent Eruption of UGC 2773-OT: finally, a decade-long extragalactic Eta Carinae analogue. mnras, 455, 3546-3560.
• , P. J., , M. T., , L. W., , A. B., , M. d., , D. H., , K. K., , N. P., , P. A., , M. P., & , M. S. (2015). Swift Ultraviolet Observations of Supernova 2014J in M82: Large Extinction from Interstellar Dust.
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  We present optical and ultraviolet (UV) photometry and spectra of the verynearby and highly reddened supernova (SN) 2014J in M82 obtained with the SwiftUltra-Violet/Optical Telescope (UVOT). Comparison of the UVOT grism spectra ofSN~2014J with Hubble Space Telescope observations of SN2011fe or UVOT grismspectra of SN~2012fr are consistent with an extinction law with a low value ofR_V~1.4. The high reddening causes the detected photon distribution in thebroadband UV filters to have a much longer effective wavelength than for anunreddened SN. The light curve evolution is consistent with this shift and doesnot show a flattening due to photons being scattered back into the line ofsight. The light curve shapes and color evolution are inconsistent with acontribution scattered into the line of sight by circumstellar dust. Weconclude that most or all of the high reddening must come from interstellardust. We show that even for a single dust composition, there is not a uniquereddening law caused by circumstellar scattering. Rather, when consideringscattering from a time-variable source, we confirm earlier studies that thereddening law is a function of the dust geometry, column density, and epoch. Wealso show how an assumed geometry of dust as a foreground sheet in mixedstellar/dust systems will lead to a higher inferred R_V. Rather than assumingthe dust around SNe is peculiar, SNe may be useful probes of the interstellarreddening laws in other galaxies.[Journal_ref: ]
• , P. J., , P. W., & , P. A. (2015). The First Ten Years of Swift Supernovae.
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  The Swift Gamma Ray Burst Explorer has proven to be an incredible platformfor studying the multiwavelength properties of supernova explosions. In itsfirst ten years, Swift has observed over three hundred supernovae. Theultraviolet observations reveal a complex diversity of behavior acrosssupernova types and classes. Even amongst the standard candle type Iasupernovae, ultraviolet observations reveal distinct groups. When the UVOT datais combined with higher redshift optical data, the relative populations ofthese groups appear to change with redshift. Among core-collapse supernovae,Swift discovered the shock breakout of two supernovae and the Swift data show adiversity in the cooling phase of the shock breakout of supernovae discoveredfrom the ground and promptly followed up with Swift. Swift observations haveresulted in an incredible dataset of UV and X-ray data for comparison withhigh-redshift supernova observations and theoretical models. Swift's supernovaprogram has the potential to dramatically improve our understanding of stellarlife and death as well as the history of our universe.[Journal_ref: ]
• Milne, P. A. (2015). Detection of a Light Echo from the Otherwise Normal SN 2007af. apj, 805, 71.
• Milne, P. A. (2015). Early Observations and Analysis of the Type Ia SN 2014J in M82. apj, 798, 39.
• Milne, P. A. (2015). Spectropolarimetry of SN 2011dh in M51: geometric insights on a Type IIb supernova progenitor and explosion. mnras, 453, 4467-4484.
• Milne, P. A. (2015). Strong near-infrared carbon in the Type Ia supernova iPTF13ebh. A&A, 578, 18.
• Milne, P. A. (2015). Swift Ultraviolet Observations of Supernova 2014J in M82: Large Extinction from Interstellar Dust. apj, 805, 74.
• Milne, P. A. (2015). The Changing Fractions of Type Ia Supernova NUV-Optical Subclasses with Redshift. apj, 779, 23.
• Milne, P. A. (2015). Theoretical Clues to the Ultraviolet Diversity of Type Ia Supernovae. apj, 809, 37-46.
• , P. J., , P. K., , R. S., , M. S., , M. d., , S. H., , K. K., , P. M., & , L. W. (2014). Ultraviolet Observations of Super-Chandrasekhar Mass Type Ia Supernova Candidates with Swift UVOT.
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  Among Type Ia supernovae (SNe~Ia) exist a class of overluminous objects whoseejecta mass is inferred to be larger than the canonical Chandrasekhar mass. Wepresent and discuss the UV/optical photometric light curves, colors, absolutemagnitudes, and spectra of three candidate Super-Chandrasekhar massSNe--2009dc, 2011aa, and 2012dn--observed with the Swift Ultraviolet/OpticalTelescope. The light curves are at the broad end for SNe Ia, with the lightcurves of SN~2011aa being amongst the broadest ever observed. We find all threeto have very blue colors which may provide a means of excluding theseoverluminous SNe from cosmological analysis, though there is some overlap withthe bluest of "normal" SNe Ia. All three are overluminous in their UV absolutemagnitudes compared to normal and broad SNe Ia, but SNe 2011aa and 2012dn arenot optically overluminous compared to normal SNe Ia. The integrated luminositycurves of SNe 2011aa and 2012dn in the UVOT range (1600-6000 Angstroms) areonly half as bright as SN~2009dc, implying a smaller 56Ni yield. While notenough to strongly affect the bolometric flux, the early time mid-UV flux makesa significant contribution at early times. The strong spectral features in themid-UV spectra of SNe 2009dc and 2012dn suggest a higher temperature and loweropacity to be the cause of the UV excess rather than a hot, smooth blackbodyfrom shock interaction. Further work is needed to determine the ejecta and 56Nimasses of SNe 2011aa and 2012dn and fully explain their high UV luminosities.[Journal_ref: ]
• Brown, P. J., Kuin, P., Scalzo, R., Smitka, M. T., Pasquale, M., Holland, S., Krisciunas, K., Milne, P., & Wang, L. (2014). Ultraviolet Observations of Super-Chandrasekhar Mass Type Ia Supernova Candidates with Swift UVOT. apj, 787, 29.
• Mauerhan, J. C., Smith, N., Silverman, J. M., Filippenko, A. V., Morgan, A. N., Cenko, S. B., Ganeshalingam, M., Clubb, K. I., Bloom, J. S., Matheson, T., & Milne, P. (2013). SN 2011ht: confirming a class of interacting supernovae with plateau light curves (Type IIn-P). mnras, 431, 2599-2611.
• McClelland, C. M., Garnavich, P. M., Milne, P. A., Shappee, B. J., & Pogge, R. W. (2013). The Mid-infrared and Optical Decay of SN 2011fe. apj, 767, 119.
• Milne, P. A., Brown, P. J., Roming, P. W., Bufano, F., & Gehrels, N. (2013). Grouping Normal Type Ia Supernovae by UV to Optical Color Differences. apj, 779, 23.
• Virgili, F. J., Mundell, C. G., Pal'shin, V., Guidorzi, C., Margutti, R., Melandri, A., Harrison, R., Kobayashi, S., Chornock, R., Henden, A., Updike, A. C., Cenko, S. B., Tanvir, N. R., Steele, I. A., Cucchiara, A., Gomboc, A., Levan, A., Cano, Z., Mottram, C. J., , Clay, N. R., et al. (2013). GRB 091024A and the Nature of Ultra-long Gamma-Ray Bursts. apj, 778, 54.
• Brown, P. J., Dawson, K. S., Harris, D. W., Olmstead, M., Milne, P., & Roming, P. W. (2012). Constraints on Type Ia Supernova Progenitor Companions from Early Ultraviolet Observations with Swift. apj, 749, 18.
• Brown, P. J., Dawson, K. S., Pasquale, M., Gronwall, C., Holland, S., Immler, S., Kuin, P., Mazzali, P., Milne, P., Oates, S., & Siegel, M. (2012). A Swift Look at SN 2011fe: The Earliest Ultraviolet Observations of a Type Ia Supernova. apj, 753, 22.
• Deason, A. J., Belokurov, V., Evans, N. W., Koposov, S. E., Cooke, R. J., Pe ~narrubia, J., Laporte, C. F., Fellhauer, M., Walker, M. G., & Olszewski, E. W. (2012). The cold veil of the Milky Way stellar halo. mnras, 425, 2840-2853.
• Ganeshalingam, M., Li, W., Filippenko, A. V., Silverman, J. M., Chornock, R., Foley, R. J., Matheson, T., Kirshner, R. P., Milne, P., Calkins, M., & Shen, K. J. (2012). The Low-velocity, Rapidly Fading Type Ia Supernova 2002es. apj, 751, 142.
• Pritchard, T. A., Roming, P. W., Brown, P. J., Kuin, N. P., Bayless, A. J., Holland, S. T., Immler, S., Milne, P., & Oates, S. R. (2012). Early Ultraviolet Observations of a Type IIn Supernova (2007pk). apj, 750, 128.
• Wang, X., Wang, L., Filippenko, A. V., Baron, E., Kromer, M., Jack, D., Zhang, T., Aldering, G., Antilogus, P., Arnett, W. D., Baade, D., Barris, B. J., Benetti, S., Bouchet, P., Burrows, A. S., Canal, R., Cappellaro, E., Carlberg, R. G., Carlo, E., , Challis, P. J., et al. (2012). Evidence for Type Ia Supernova Diversity from Ultraviolet Observations with the Hubble Space Telescope. apj, 749, 126.

Proceedings Publications

• Bilinski, C., Williams, G. G., Smith, P. S., Smith, N., Milne, P., Hoffman, J. L., Huk, L. N., Leonard, D. C., & Dessart, L. (2014, jan). The Supernova Spectropolarimetry Project: Results from Multi-Epoch Observations of the Type IIb SN 2011dh. In American Astronomical Society Meeting Abstracts, 223, #354.23.
• Hoffman, J. L., Smith, N., Bilinski, C., Dessart, L., Huk, L. N., Leonard, D. C., Milne, P., Smith, P. S., & Williams, G. (2014, jan). The Supernova Spectropolarimetry Project: Evolution of Asymmetries in the Very Luminous Type Ib SN 2012au. In American Astronomical Society Meeting Abstracts, 223, #354.21.
• Khandrika, H. G., Leonard, D. C., Horst, C., Rachubo, A., Duong, N., Williams, G. G., Smith, P. S., Smith, N., Milne, P., Hoffman, J. L., Huk, L. N., & Dessart, L. (2014, jun). The Supernova Spectropolarimetry Project: Photometric Followup in the Optical and Near- Infrared by the Mount Laguna Supernova Survey. In American Astronomical Society Meeting Abstracts, 224, #121.16.
• Milne, P., Williams, G., Smith, P. S., & Smith, N. (2014, jan). Spectropolarimetry of SN 2011fe. In American Astronomical Society Meeting Abstracts, 223, #354.39.
• Olsen, K. A., Nidever, D. L., Gruendl, R. A., Blum, R. D., Walker, A. R., Saha, A., Olszewski, E. W., Munoz, R., Kunder, A. M., Kaleida, C. C., Conn, B., Besla, G., Majewski, S. R., Gallart, C., Monelli, M., Stringfellow, G. S., Zaritsky, D. F., Chu, Y., Van Der Marel, R. P., , Martin, N., et al. (2014, jan). SMASH: The Survey of the MAgellanic Stellar History. In American Astronomical Society Meeting Abstracts, 223, #254.44.
• Saha, A., Narayan, G., Matheson, T., Holberg, J. B., Stubbs, C., Deustua, S. E., Bohlin, R., Olszewski, E. W., Gilliland, R. L., Axelrod, T. S., & Rest, A. (2014, jun). Establishing a Network of Next Generation SED Standards with DA White Dwarfs. In American Astronomical Society Meeting Abstracts, 224, #319.04.
• Williams, G. G., Dessart, L., Hoffman, J. L., Huk, L. N., Leonard, D. C., Milne, P., Smith, N., & Smith, P. S. (2014, jan). The Supernova Spectropolarimetry Project: Results from Multi-Epoch Observations of the Type IIn SN 2010jl. In American Astronomical Society Meeting Abstracts, 223, #354.22.
• Bryngelson, G. L., Leising, M. D., & Milne, P. (2013, jan). The BVRIJH Power of 3 Thermonuclear Supernovae Out to 500 Days. In American Astronomical Society Meeting Abstracts, 221, #253.05.
• Drozdov, D., Leising, M. D., Milne, P., & Riess, A. G. (2013, jun). The Detection of a Light Echo from Type Ia SN 2007af in NGC 5584. In American Astronomical Society Meeting Abstracts, 222, #118.04.
• Garnavich, P. M., Milne, P., Bryngelson, G. L., & Leising, M. D. (2013, jun). A Light Echo Candidate from Supernova 2009ig. In American Astronomical Society Meeting Abstracts, 222, #209.04.
• Kilgore, E., Leising, M. D., Bryngelson, G. L., Milne, P., & Lair, J. C. (2013, jan). Late Light Curves of the Subluminous SN 2005mz. In American Astronomical Society Meeting Abstracts, 221, #253.08.
• Lair, J. C., Kilgore, E. E., Milne, P., Bryngelson, G. L., & Leising, M. D. (2013, jan). Late Light Curves of SN 2002cx-like Type Ia Supernovae. In American Astronomical Society Meeting Abstracts, 221, #253.09.
• McClelland, C., Garnavich, P. M., Milne, P., Shappee, B., & Pogge, R. W. (2013, jun). The Mid-Infrared and Optical Decay of SN 2011fe. In American Astronomical Society Meeting Abstracts, 222, #118.06.
• Williams, G. G., Smith, P., Smith, N., Milne, P., Hoffman, J., Huk, L., Leonard, D., & Dessart, L. (2012, may). The Supernova Spectropolarimetry Project; A Study of the Evolution of Aspherical Stellar Explosions. In American Astronomical Society Meeting Abstracts #220, 220, #523.24.

Poster Presentations

• Williams, G. G., Smith, P. S., Smith, N., Milne, P. A., Bilinski, C., Dessart, L., Hoffman, J., Leonard, D., Huk, L., Mauerhan, J., & Porter, A. (2016, 2016-05-16). The Supernova Spectropolarimetry Project. The Transient Sky. Cambridge, MA: Harvard-Smithsonian Center for Astrophysics.