Results for "Ryan J. Foley"

total 185112took 0.20s
On Spectral Line Profiles in Type Ia Supernova SpectraDec 26 2012Jan 02 2013We present a detailed analysis of spectral line profiles in Type Ia supernova (SN Ia) spectra. We focus on the feature at ~3500 - 4000 A, which is commonly thought to be caused by blueshifted absorption of Ca H&K. Unlike some other spectral features in ... More
The Dusty Progenitor Star of the Type II Supernova 2017eawJun 01 2018We present pre-explosion photometry of the likely progenitor star of the Type II supernova (SN II) 2017eaw in NGC 6946. We use a Hubble Space Telescope (HST) image of SN 2017eaw to perform relative astrometry with HST and Spitzer Space Telescope (Spitzer) ... More
Circumstellar absorption in double detonation Type Ia supernovaeFeb 12 2013May 06 2013Upon formation, degenerate He core white dwarfs are surrounded by a radiative H-rich layer primarily supported by ideal gas pressure. In this Letter, we examine the effect of this H-rich layer on mass transfer in He+C/O double white dwarf binaries that ... More
Luminosity Indicators in the Ultraviolet Spectra of Type Ia SupernovaeMar 07 2008May 02 2008We present a complete sample of International Ultraviolet Explorer and Hubble Space Telescope ultraviolet (UV) spectra of Type Ia supernovae (SNe Ia) through 2004. We measure the equivalent width (EW) and blueshifted velocity of the minimum of the one ... More
Dust Formation and He II 4686 emission in the Dense Shell of the Peculiar Type Ib Supernova 2006jcApr 17 2007Feb 25 2008We present evidence for the formation of dust grains in an unusual Type Ib SN based on late-time spectra of SN 2006jc. The progenitor suffered an LBV-like outburst just 2 yr earlier, and we propose that the dust formation is a consequence of the SN blast ... More
Velocity Evolution and the Intrinsic Color of Type Ia SupernovaeJul 18 2011Sep 14 2011To understand how best to use observations of Type Ia supernovae (SNe Ia) to obtain precise and accurate distances, we investigate the relations between spectra of SNe Ia and their intrinsic colors. Using a sample of 1630 optical spectra of 255 SNe, based ... More
Spectropolarimetry of the Peculiar Type Ia SN 2005hkMar 03 2006Mar 10 2006We present Keck spectropolarimetry of the unusual type Ia supernova (SN Ia) 2005hk several days before maximum light. An analysis of the high signal-to-noise-ratio total-flux spectrum shows the object's extreme similarity to the peculiar SN 2002cx. SN ... More
Spectral Evolution of the Extraordinary Type IIn Supernova 2006gyJun 11 2009Jun 13 2009We present a detailed analysis of the extremely luminous Type IIn supernova SN2006gy using spectra obtained between days 36 and 237 after explosion. We derive the temporal evolution of the effective temperature, radius, expansion speeds, and bolometric ... More
The Changing Fractions of Type Ia Supernova NUV-Optical Subclasses with RedshiftAug 07 2014UV and optical photometry of Type Ia supernovae (SNe Ia) at low redshift have revealed the existence of two distinct color groups, NUV-red and NUV-blue events. The color curves differ primarily by an offset, with the NUV-blue u- color curves bluer than ... More
SN 2006tf: Precursor Eruptions and the Optically Thick Regime of Extremely Luminous Type IIn SupernovaeMar 31 2008Aug 04 2008SN2006tf is the third most luminous SN discovered so far, after SN2005ap and SN2006gy. SN2006tf is valuable because it provides a link between two regimes: (1) luminous type IIn supernovae powered by emission directly from interaction with circumstellar ... More
Late-Time Spectroscopy of SN 2002cx: The Prototype of a New Subclass of Type Ia SupernovaeFeb 10 2006Apr 04 2006We present Keck optical spectra of SN 2002cx, the most peculiar known Type Ia supernova (SN Ia), taken 227 and 277 days past maximum light. Astonishingly, the spectra are not dominated by the forbidden emission lines of iron that are a hallmark of thermonuclear ... More
Optical Spectroscopy of the Somewhat Peculiar Type IIb Supernova 2001igMar 24 2009May 22 2009Here we present previously unpublished optical spectra of supernova (SN) 2001ig, a Type IIb SN, from about a week after explosion until nearly one year later. The earliest spectrum consists of only a few broad absorption features, but soon more common ... More
The Type Ia Supernova Color-Magnitude Relation and Host Galaxy Dust: A Simple Hierarchical Bayesian ModelSep 14 2016Conventional Type Ia supernova (SN Ia) cosmology analyses currently use a simplistic linear regression of magnitude versus color and light curve shape, which does not model intrinsic SN Ia variations and host galaxy dust as physically distinct effects, ... More
Tidal Disruption Event Host Galaxies in the Context of the Local Galaxy PopulationJul 05 2017Nov 14 2017We study the properties of tidal disruption event (TDE) host galaxies in the context of a catalog of ~500,000 galaxies from the Sloan Digital Sky Survey. We explore whether selection effects can account for the overrepresentation of TDEs in E+A/post-starburst ... More
Constraining Type Ia Supernova Progenitor Scenarios with Extremely Late-time Photometry of Supernova SN 2013aaFeb 06 2018Apr 13 2018We present Hubble Space Telescope observations and photometric measurements of the Type Ia supernova (SN Ia) SN 2013aa 1500 days after explosion. At this epoch, the luminosity is primarily dictated by the amounts of radioactive ${}^{57}\textrm{Co}$ and ... More
A perturbative determination of the parameters of an anisotropic quark actionOct 04 2004The parameters of a 3+1 anisotropic quark action with Symanzik-improved glue are determined at 1-loop in perturbation theory.
Early and Late-Time Observations of SN 2008ha: Additional Constraints for the Progenitor and ExplosionDec 03 2009We present a new maximum-light optical spectrum of the the extremely low luminosity and exceptionally low energy Type Ia supernova (SN Ia) 2008ha, obtained one week before the earliest published spectrum. Previous observations of SN 2008ha were unable ... More
SN 2006bt: A Perplexing, Troublesome, and Possibly Misleading Type Ia SupernovaDec 01 2009SN 2006bt displays characteristics unlike those of any other known Type Ia supernova (SN Ia). We present optical light curves and spectra of SN 2006bt which demonstrate the peculiar nature of this object. SN 2006bt has broad, slowly declining light curves ... More
Color Dispersion and Milky Way Reddening Among Type Ia SupernovaeJun 18 2013Past analyses of Type Ia Supernovae (SNe Ia) have identified an irreducible scatter of 5-10% in distance widely attributed to an intrinsic dispersion in luminosity. Another, equally valid, source of this scatter is intrinsic dispersion in color. Misidentification ... More
SN 2006gy: Discovery of the most luminous supernova ever recorded, powered by the death of an extremely massive star like Eta CarinaeDec 21 2006May 22 2007(abridged) We report our discovery and observations of the peculiar Type IIn supernova SN2006gy in NGC1260, revealing that it reached a peak magnitude of -22, making it the most luminous supernova ever recorded. It is not yet clear what powers the total ... More
The binary progenitor of Tycho Brahe's 1572 supernovaOct 28 2004The brightness of type Ia supernovae, and their homogeneity as a class, makes them powerful tools in cosmology, yet little is known about the progenitor systems of these explosions. They are thought to arise when a white dwarf accretes matter from a companion ... More
The Low-Velocity, Rapidly Fading Type Ia Supernova 2002esFeb 14 2012SN 2002es is a peculiar subluminous Type Ia supernova (SN Ia) with a combination of observed characteristics never before seen in a SN Ia. At maximum light, SN 2002es shares spectroscopic properties with the underluminous SN 1991bg subclass of SNe Ia, ... More
The Calibration of the Swift/UVOT Optical Observations: A Recipe for PhotometryMay 25 2005Sep 27 2005Swift/UVOT has the capability to provide critical insight into the physics of the early afterglows of gamma-ray bursts (GRBs). But without precise calibration of the UVOT to standard photometric systems, it is impossible to leverage late- time, ground-based ... More
Late-time Spectroscopy of Type Iax SupernovaeJan 22 2016We examine the late-time (t > 200 days after peak brightness) spectra of Type Iax supernovae (SNe Iax), a low-luminosity, low-energy class of thermonuclear stellar explosions observationally similar to, but distinct from, Type Ia supernovae. We present ... More
Possible Detection of the Stellar Donor or Remnant for the Type Iax Supernova 2008haAug 05 2014Type Iax supernovae (SNe Iax) are thermonuclear explosions that are related to SNe Ia, but are physically distinct. The most important differences are that SNe Iax have significantly lower luminosity (1% - 50% that of typical SNe Ia), lower ejecta mass ... More
The Chemical Abundances of Tycho G in Supernova Remnant 1572Sep 03 2008We present an analysis of the chemical abundances of the star Tycho G in the direction of the remnant of supernova (SN) 1572, based on Keck high-resolution optical spectra. The stellar parameters of this star are found to be those of a G-type subgiant ... More
Nearby Supernova Rates from the Lick Observatory Supernova Search. II. The Observed Luminosity Functions and Fractions of Supernovae in a Complete SampleJun 23 2010Dec 07 2010This is the second paper of a series in which we present new measurements of the observed rates of supernovae (SNe) in the local Universe, determined from the Lick Observatory Supernova Search (LOSS). In this paper, a complete SN sample is constructed, ... More
Coronal lines and dust formation in SN 2005ip: Not the brightest, but the hottest Type IIn supernovaSep 29 2008Apr 10 2009We present optical photometry and spectroscopy of SN2005ip for the first 3yr after discovery, showing an underlying Type II-L SN interacting with a steady wind to yield an unusual Type IIn spectrum. For the first 160d, it had a fast linear decline from ... More
A Spectroscopic Study of Type Ibc Supernova Host Galaxies from Untargeted SurveysJun 12 2012Sep 16 2012We present the largest spectroscopic study of the host environments of Type Ibc supernovae (SN Ibc) discovered exclusively by untargeted SN searches. Past studies of SN Ibc host environments have been biased towards high-mass, high-metallicity galaxies ... More
The Role of Plate Tectonic-Climate Coupling and Exposed Land Area in the Development of Habitable Climates on Rocky PlanetsSep 01 2015The long-term carbon cycle is vital for maintaining liquid water oceans on rocky planets due to the negative climate feedbacks involved in silicate weathering. Plate tectonics plays a crucial role in driving the long-term carbon cycle because it is responsible ... More
Habitability of Earth-like stagnant lid planets: Climate evolution and recovery from snowball statesMar 28 2019Coupled models of mantle thermal evolution, volcanism, outgassing, weathering, and climate evolution for Earth-like (in terms of size and composition) stagnant lid planets are used to assess their prospects for habitability. The results indicate that ... More
Radial and orbital excitations of static-light mesonsFeb 06 2007We present results for the spectrum of static-light mesons from Nf=2 lattice QCD. These results were obtained using all-to-all light quark propagators on an anisotropic lattice, yielding an improved signal resolution when compared to more conventional ... More
A non-perturbative study of the action parameters for anisotropic-lattice quarksMay 28 2004A quark action designed for highly anisotropic lattice simulations is discussed. The mass-dependence of the parameters in the action is studied and the results are presented. Applications of this action in studies of heavy quark quantities are described ... More
The Diversity of Massive Star Outbursts I: Observations of SN 2009ip, UGC 2773 OT2009-1, and Their ProgenitorsFeb 03 2010Despite both being outbursts of luminous blue variables (LBVs), SN 2009ip and UGC 2773 OT2009-1 have very different progenitors, spectra, circumstellar environments, and possibly physical mechanisms that generated the outbursts. From pre-eruption HST ... More
Significant Luminosity Differences of Two Twin Type Ia SupernovaeJun 21 2018The Type Ia supernovae (SNe Ia) 2011by, hosted in NGC 3972, and 2011fe, hosted in M101, are optical "twins," having almost identical optical light-curve shapes, colours, and near-maximum-brightness spectra. However, SN 2011fe had significantly more ultraviolet ... More
The long-term evolution and appearance of Type Iax postgenitor starsDec 20 2018Type Iax supernovae may arise from failed explosions of white dwarfs that leave behind a bound remnant (i.e., a "postgenitor" star) that could be identified in wide field surveys. To understand their observational signatures, we simulate these white dwarf ... More
Static-light mesons on a dynamical anisotropic latticeOct 09 2006We present results for the spectrum of static-light mesons from Nf=2 lattice QCD. These results were obtained using all-to-all light quark propagators on an anisotropic lattice, yielding an improved signal resolution when compared to more conventional ... More
The long-term evolution and appearance of Type Iax postgenitor starsDec 20 2018Mar 01 2019Type Iax supernovae may arise from failed explosions of white dwarfs that leave behind a bound remnant (i.e., a "postgenitor" star) that could be identified in wide field surveys. To understand their observational signatures, we simulate these white dwarf ... More
Heavy hadrons on an anisotropic latticeSep 25 2003Results from simulations of quarkonia and heavy-light mesons on an anisotropic lattice are presented. The improved quark action and action-parameter tuning used in this study are discussed.
A luminous, blue progenitor system for a type-Iax supernovaAug 05 2014Type-Iax supernovae (SN Iax) are stellar explosions that are spectroscopically similar to some type-Ia supernovae (SN Ia) at maximum light, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic ... More
A 2.4% Determination of the Local Value of the Hubble ConstantApr 05 2016Jun 09 2016We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant (H_0) from 3.3% to 2.4%. Improvements come from new, near-infrared observations of Cepheid variables in 11 new ... More
Short GRB 130603B: Discovery of a jet break in the optical and radio afterglows, and a mysterious late-time X-ray excessSep 28 2013We present radio, optical/NIR, and X-ray observations of the afterglow of the short-duration 130603B, and uncover a break in the radio and optical bands at 0.5 d after the burst, best explained as a jet break with an inferred jet opening angle of 4-8 ... More
Linking Type Ia Supernova Progenitors and their Resulting ExplosionsMar 13 2012Apr 19 2012Comparing the ejecta velocities at maximum brightness and narrow circumstellar/interstellar Na D absorption line profiles of a sample of 23 Type Ia supernovae (SNe Ia), we determine that the properties of SN Ia progenitor systems and explosions are intimately ... More
Twins for life? A comparative analysis of the Type Ia supernovae 2011fe and 2011byAug 12 2014The nearby Type Ia supernovae (SNe Ia) 2011fe and 2011by had nearly identical photospheric phase optical spectra, light-curve widths, and photometric colours, but at peak brightness SN 2011by reached a fainter absolute magnitude in all optical bands and ... More
On the Progenitor of the Type IIb Supernova 2016gkgOct 14 2016We present a detection in pre-explosion Hubble Space Telescope (HST) imaging of a point source consistent with being the progenitor star of the Type IIb supernova (SN IIb) 2016gkg. Post-explosion imaging from the Keck Adaptive Optics system was used to ... More
The Multi-Epoch Nearby Cluster Survey: type Ia supernova rate measurement in z~0.1 clusters and the late-time delay time distributionOct 07 2011Dec 27 2011We describe the Multi-Epoch Nearby Cluster Survey (MENeaCS), designed to measure the cluster Type Ia supernova (SN Ia) rate in a sample of 57 X-ray selected galaxy clusters, with redshifts of 0.05 < z < 0.15. Utilizing our real time analysis pipeline, ... More
On the Progenitor System of the Type Iax Supernova 2014dt in M61Dec 02 2014We present pre-explosion and post-explosion Hubble Space Telescope images of the Type Iax supernova (SN Iax) 2014dt in M61. After astrometrically aligning these images, we do not detect any stellar sources at the position of the SN in the pre-explosion ... More
Constraining Type Iax Supernova Progenitor Systems with Stellar Population AgingJan 16 2019Type Iax supernovae (SNe~Iax) are the most common class of peculiar SNe. While they are thought to be thermonuclear white-dwarf (WD) SNe, SNe~Iax are observationally similar to, but distinct from SNe~Ia. Unlike SNe~Ia, where roughly 30\% occur in early-type ... More
Scaling Laws for Convection with Temperature-dependent Viscosity and Grain-damageOct 28 2014Numerical experiments of convection with grain-damage are used to develop scaling laws for convective heat flow, mantle velocity, and plate velocity across the stagnant lid and plate-tectonic regimes. Three main cases are presented in order of increasing ... More
X-ray Limits on the Progenitor System of the Type Ia Supernova 2017ejbJun 21 2018We present deep X-ray limits on the presence of a pre-explosion counterpart to the low-luminosity Type Ia supernova (SN Ia) 2017ejb. SN 2017ejb was discovered in NGC 4696, a well-studied elliptical galaxy in the Centaurus cluster with 894 ks of Chandra ... More
After the Fall: Late-Time Spectroscopy of Type IIP SupernovaeOct 24 2016Dec 08 2016Herein we analyse late-time (post-plateau; 103 < t < 1229 d) optical spectra of low-redshift (z < 0.016), hydrogen-rich Type IIP supernovae (SNe IIP). Our newly constructed sample contains 91 nebular spectra of 38 SNe IIP, which is the largest dataset ... More
After the Fall: Late-Time Spectroscopy of Type IIP SupernovaeOct 24 2016Herein we analyse late-time (post-plateau; 103 < t < 1229 d) optical spectra of low-redshift (z < 0.016), hydrogen-rich Type IIP supernovae (SNe IIP). Our newly constructed sample contains 91 nebular spectra of 38 SNe IIP, which is the largest dataset ... More
Photometric and Spectroscopic Properties of Type II-P SupernovaeApr 01 2014Sep 20 2014We study a sample of 23 Type II Plateau supernovae (SNe II-P), all observed with the same set of instruments. Analysis of their photometric evolution confirms that their typical plateau duration is 100 days with little scatter, showing a tendency to get ... More
SN 2008ha: An Extremely Low Luminosity and Extremely Low Energy SupernovaFeb 16 2009Feb 23 2009We present ultraviolet, optical, and near-infrared photometry as well as optical spectra of the peculiar supernova (SN) 2008ha. SN 2008ha had a very low peak luminosity, reaching only M_V = -14.2 mag, and low line velocities of only ~2000 km/s near maximum ... More
Revisiting the Lick Observatory Supernova Search Volume-Limited Sample: Updated Classifications and Revised Stripped-Envelope Supernova FractionsSep 09 2016Jan 11 2017We re-examine the classifications of supernovae (SNe) presented in the Lick Observatory Supernova Search (LOSS) volume-limited sample with a focus on the stripped-envelope SNe. The LOSS volume-limited sample, presented by Leaman et al. (2011) and Li et ... More
Optical Identification of Cepheids in 19 Host Galaxies of Type Ia Supernovae and NGC 4258 with the Hubble Space TelescopeJul 28 2016Aug 01 2016We present results of an optical search for Cepheid variable stars using the Hubble Space Telescope (HST) in 19 hosts of Type Ia supernovae (SNe Ia) and the maser-host galaxy NGC 4258, conducted as part of the SH0ES project (Supernovae and H0 for the ... More
Carbon cycling and habitability of Earth-size stagnant lid planetsDec 11 2017Models of thermal evolution, crustal production, and CO$_2$ cycling are used to constrain the prospects for habitability of rocky planets, with Earth-like size and composition, in the stagnant lid regime. Specifically, we determine the conditions under ... More
The Relation Between Ejecta Velocity, Intrinsic Color, and Host-Galaxy Mass for High-Redshift Type Ia SupernovaeJan 31 2012Recently, using a large low-redshift sample of Type Ia supernovae (SNe Ia), we discovered a relation between SN Ia ejecta velocity and intrinsic color that improves the distance precision of SNe Ia and reduces potential systematic biases related to dust ... More
Kinematics and Host-Galaxy Properties Suggest a Nuclear Origin for Calcium-Rich Supernova ProgenitorsJan 29 2015Calcium-rich supernovae (Ca-rich SNe) are peculiar low-luminosity SNe Ib with relatively strong Ca spectral lines at ~2 months after peak brightness. This class also has an extended projected offset distribution, with several members of the class offset ... More
A non-spherical core in the explosion of supernova SN 2004djMar 13 2006An important and perhaps critical clue to the mechanism driving the explosion of massive stars as supernovae is provided by the accumulating evidence for asymmetry in the explosion. Indirect evidence comes from high pulsar velocities, associations of ... More
Dust and the type II-Plateau supernova 2004djMar 15 2011Apr 13 2011We present mid-infrared (MIR) spectroscopy of a Type II-plateau supernova, SN 2004dj, obtained with the Spitzer Space Telescope, spanning 106--1393 d after explosion. MIR photometry plus optical/near-IR observations are also reported. An early-time MIR ... More
Ultraviolet Diversity of Type Ia SupernovaeApr 04 2016Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) probe the outermost layers of the explosion, and UV spectra of SNe Ia are expected to be extremely sensitive to differences in progenitor composition and the details of the explosion. Here we ... More
Late-time observations of SN2006gy: Still Going StrongFeb 13 2008Jul 08 2008Owing to its extremely high luminosity and long duration, SN2006gy radiated more energy in visual light than any other known SN. Two hypotheses to explain its high luminosity -- that it was powered by shock interaction with CSM as implied by its Type ... More
The Subluminous Supernova 2007qd: A Missing Link in a Family of Low-Luminosity Type Ia SupernovaeJul 16 2010We present multi-band photometry and multi-epoch spectroscopy of the peculiar Type Ia supernova (SN Ia) 2007qd, discovered by the SDSS-II Supernova Survey. It possesses physical properties intermediate to those of the peculiar SN 2002cx and the extremely ... More
Searching for Highly Magnified Stars at Cosmological Distances: Discovery of a Redshift 0.94 Blue Supergiant in Archival Images of the Galaxy Cluster MACS J0416.1-2403Feb 14 2019Individual highly magnified stars have been recently discovered at lookback times of more than half the age of the Universe, in lensed galaxies that straddle the critical curves of massive galaxy clusters. Having confirmed their detectability, it is now ... More
Excited-Nucleon Spectroscopy with 2+1 Fermion FlavorsNov 17 2009We present progress made by the Hadron Spectrum Collaboration (HSC) in determining the tower of excited nucleon states using 2+1-flavor anisotropic clover lattices. The HSC has been investigating interpolating operators projected into irreducible representations ... More
A Deep Search for Prompt Radio Emission from Thermonuclear Supernovae with the Very Large ArrayOct 26 2015Searches for circumstellar material around Type Ia supernovae (SNe Ia) are one of the most powerful tests of the nature of SN Ia progenitors, and radio observations provide a particularly sensitive probe of this material. Here we report radio observations ... More
Optical and Near-Infrared Observations of the Highly Reddened, Rapidly Expanding Type Ia Supernova 2006X in M100Aug 01 2007Nov 16 2007We present extensive optical (UBVRI), near-infrared (JK) light curves and optical spectroscopy of the Type Ia supernova (SN) 2006X in the nearby galaxy NGC 4321 (M100). Our observations suggest that either SN 2006X has an intrinsically peculiar color ... More
Connecting the progenitors, pre-explosion variability, and giant outbursts of luminous blue variables with Gaia16cfrJun 29 2017Oct 12 2017We present multi-epoch, multi-colour pre-outburst photometry and post-outburst light curves and spectra of the luminous blue variable (LBV) outburst Gaia16cfr discovered by the Gaia satellite on 1 December 2016. We detect Gaia16cfr in 13 epochs of Hubble ... More
Spitzer measurements of atomic and molecular abundances in the Type IIP SN 2005afSep 26 2006We present results based on Spitzer Space Telescope mid-infrared (3.6-30 micron) observations of the nearby IIP supernova 2005af. We report the first ever detection of the SiO molecule in a Type IIP supernova. Together with the detection of the CO fundamental, ... More
The Type IIb Supernova 2013df and Its Cool Supergiant ProgenitorDec 13 2013We have obtained early-time photometry and spectroscopy of Supernova (SN) 2013df in NGC 4414. The SN is clearly of Type IIb, with notable similarities to SN 1993J. From its luminosity at secondary maximum light, it appears that less $^{56}$Ni ($\lesssim ... More
A Potential Progenitor for the Type Ic Supernova 2017einAug 09 2018We report the first detection of a credible progenitor system for a Type Ic supernova (SN Ic), SN 2017ein. We present spectra and photometry of the SN, finding it to be similar to carbon-rich, low-luminosity SNe Ic. Using a post-explosion Keck adaptive ... More
A Mismatch in the Ultraviolet Spectra between Low-Redshift and Intermediate-Redshift Type Ia Supernovae as a Possible Systematic Uncertainty for Supernova CosmologyOct 13 2010Feb 14 2012We present Keck high-quality rest-frame ultraviolet (UV) through optical spectra of 21 Type Ia supernovae (SNe Ia) in the redshift range 0.11 < z < 0.37 and a mean redshift of 0.22 that were discovered during the Sloan Digital Sky Survey-II (SDSS-II) ... More
Keck and ESO-VLT View of the Symmetry of the Ejecta of the XRF/SN 2006ajMar 06 2007Nebular-phase spectra of SN 2006aj, which was discovered in coincidence with X-ray flash 060218, were obtained with Keck in 2006 July and the Very Large Telescope in 2006 September. At the latter epoch spectropolarimetry was also attempted, yielding an ... More
The Candidate Progenitor of the Type IIn SN 2010jl is Not an Optically Luminous StarNov 01 2016The nature of the progenitor star (or system) for the Type IIn supernova (SN) subclass remains uncertain. While there are direct imaging constraints on the progenitors of at least four Type IIn supernovae, one of them being SN 2010jl, ambiguities remain ... More
The Massive Progenitor of the Possible Type II-Linear Supernova 2009hd in Messier 66Aug 12 2011We present observations of SN2009hd in the nearby galaxy M66. This SN is one of the closest to us in recent years but heavily obscured by dust, rendering it unusually faint in the optical, given its proximity. We find that the observed properties of SN2009hd ... More
Static-light hadrons on a dynamical anisotropic latticeNov 02 2005We present preliminary results for the static-light meson and baryon spectra for $N_f=2$ QCD. The study is performed on an anisotropic lattice and uses a new all-to-all propagator method allowing us to determine particle masses to a high precision.
Practical all-to-all propagators for lattice QCDMay 20 2005A new method for computing all elements of the lattice quark propagator is proposed. The method combines the spectral decomposition of the propagator, computing the lowest eigenmodes exactly, with noisy estimators which are 'diluted', i.e. taken to have ... More
A luminosity distribution for kilonovae based on short gamma-ray burst afterglowsNov 13 2018The combined detection of a gravitational-wave signal, kilonova, and short gamma-ray burst (sGRB) from GW170817 marked a scientific breakthrough in the field of multi-messenger astronomy. But even before GW170817, there have been a number of sGRBs with ... More
Dust and the type II-plateau supernova 2004etApr 23 2009Sep 08 2009We present mid-infrared (MIR) observations of the Type II-plateau supernova (SN) 2004et, obtained with the {\it Spitzer Space Telescope} between days 64 and 1406 past explosion. Late-time optical spectra are also presented. For the period 300-795 days ... More
Supernovae in the Subaru Deep Field: An Initial Sample, and Type Ia Rate, out to Redshift 1.6Jul 03 2007Sep 05 2007Large samples of high-redshift supernovae (SNe) are potentially powerful probes of cosmic star formation, metal enrichment, and SN physics. We present initial results from a new deep SN survey, based on re-imaging in the R, i', z' bands, of the 0.25 deg2 ... More
First results from 2+1 dynamical quark flavors on an anisotropic lattice: light-hadron spectroscopy and setting the strange-quark massOct 20 2008We present the first light-hadron spectroscopy on a set of $N_f=2+1$ dynamical, anisotropic lattices. A convenient set of coordinates that parameterize the two-dimensional plane of light and strange-quark masses is introduced. These coordinates are used ... More
Spectroscopic Discovery of the Broad-Lined Type Ic Supernova 2010bh Associated with the Low-Redshift GRB 100316DApr 13 2010We present the spectroscopic discovery of a broad-lined Type Ic supernova (SN 2010bh) associated with the nearby long-duration gamma-ray burst (GRB) 100316D. At z = 0.0593, this is the third-nearest GRB-SN. Nightly optical spectra obtained with the Magellan ... More
Improved Standardization of Type II-P Supernovae: Application to an Expanded SampleOct 27 2008Jan 08 2009In the epoch of precise and accurate cosmology, cross-confirmation using a variety of cosmographic methods is paramount to circumvent systematic uncertainties. Owing to progenitor histories and explosion physics differing from those of Type Ia SNe (SNe ... More
Measuring Ejecta Velocity Improves Type Ia Supernova DistancesNov 19 2010We use a sample of 121 spectroscopically normal Type Ia supernovae (SNe Ia) to show that their intrinsic color is correlated with their ejecta velocity, as measured from the blueshift of the Si II 6355 feature near maximum brightness, v_Si. The SN Ia ... More
Classifying Supernovae Using Only Galaxy DataSep 10 2013Oct 23 2013We present a new method for probabilistically classifying supernovae (SNe) without using SN spectral or photometric data. Unlike all previous studies to classify SNe without spectra, this technique does not use any SN photometry. Instead, the method relies ... More
Minimal Bratteli diagrams and dimension groups of AF C*-algebrasOct 22 2003A method is described which identifies a wide variety of AF algebra dimension groups with groups of continuous functions. Since the continuous functions in these groups have domains which correspond to the set of all infinite paths in what will be called ... More
The Foundation Supernova Survey: Motivation, Design, Implementation, and First Data ReleaseNov 06 2017The Foundation Supernova Survey aims to provide a large, high-fidelity, homogeneous, and precisely-calibrated low-redshift Type Ia supernova (SN Ia) sample for cosmology. The calibration of the current low-redshift SN sample is the largest component of ... More
Very Early Ultraviolet and Optical Observations of the Type Ia Supernova 2009igSep 05 2011Nov 01 2011Supernova (SN) 2009ig was discovered 17 hours after explosion by the Lick Observatory Supernova Search, promptly classified as a normal Type Ia SN (SN Ia), peaked at V = 13.5 mag, and was equatorial, making it one of the foremost supernovae for intensive ... More
Detection of Circumstellar Helium in Type Iax Progenitor SystemsDec 31 2018May 09 2019We present direct spectroscopic modeling of 44 Type Iax supernovae (SNe Iax) using spectral synthesis code SYNAPPS. We confirm detections of helium emission in the early-time spectra of two SNe Iax: SNe 2004cs and 2007J. These He I features are better ... More
The Berkeley Sample of Stripped-Envelope SupernovaeOct 08 2018Oct 10 2018We present the complete sample of stripped-envelope supernova (SN) spectra observed by the Lick Observatory Supernova Search (LOSS) collaboration over the last three decades: 888 spectra of 302 SNe, 652 published here for the first time, with 384 spectra ... More
Type Iax Supernovae: A New Class of Stellar ExplosionDec 10 2012Feb 04 2013We describe observed properties of the Type Iax class of supernovae (SNe Iax), consisting of SNe observationally similar to its prototypical member, SN 2002cx. The class currently has 25 members, and we present optical photometry and/or optical spectroscopy ... More
Initiation of Plate Tectonics from Post-Magma Ocean Thermo-Chemical ConvectionOct 28 2014Leading theories for the presence of plate tectonics on Earth typically appeal to the role of present day conditions in promoting rheological weakening of the lithosphere. However, it is unknown whether the conditions of the early Earth were favorable ... More
Three Hypervelocity White Dwarfs in Gaia DR2: Evidence for Dynamically Driven Double-Degenerate Double-Detonation Type Ia SupernovaeApr 30 2018Jul 18 2018Double detonations in double white dwarf (WD) binaries undergoing unstable mass transfer have emerged in recent years as one of the most promising Type Ia supernova (SN Ia) progenitor scenarios. One potential outcome of this "dynamically driven double-degenerate ... More
High-Velocity Line Forming Regions in the Type Ia Supernova 2009igFeb 14 2013Aug 29 2013We report measurements and analysis of high-velocity (> 20,000 km/s) and photospheric absorption features in a series of spectra of the Type Ia supernova (SN) 2009ig obtained between -14d and +13d with respect to the time of maximum B-band luminosity. ... More
Extensive HST Ultraviolet Spectra and Multi-wavelength Observations of SN 2014J in M82 Indicate Reddening and Circumstellar Scattering by Typical DustMay 14 2014Jul 14 2014SN 2014J in M82 is the closest detected Type Ia supernova (SN Ia) in at least 28 years and perhaps in 410 years. Despite its small distance of 3.3 Mpc, SN 2014J is surprisingly faint, peaking at V = 10.6 mag, and assuming a typical SN Ia luminosity, we ... More
A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17aOct 16 2017The merging neutron star gravitational wave event GW170817 has been observed throughout the entire electromagnetic spectrum from radio waves to $\gamma$-rays. The resulting energetics, variability, and light curves are shown to be consistent with GW170817 ... More
Electromagnetic Evidence that SSS17a is the Result of a Binary Neutron Star MergerOct 16 201711 hours after the detection of gravitational wave source GW170817 by the Laser Interferometer Gravitational-Wave Observatory and Virgo Interferometers, an associated optical transient SSS17a was discovered in the galaxy NGC 4993. While the gravitational ... More
The Unprecedented Properties of the First Electromagnetic Counterpart to a Gravitational Wave SourceOct 16 2017We discovered Swope Supernova Survey 2017a (SSS17a) in the LIGO/Virgo Collaboration (LVC) localization volume of GW170817, the first detected binary neutron star (BNS) merger, only 10.9 hours after the trigger. No object was present at the location of ... More
Hubble Space Telescope and Ground-Based Observations of the Type Iax Supernovae SN 2005hk and SN 2008ASep 17 2013Apr 25 2014We present Hubble Space Telescope (HST) and ground-based optical and near-infrared observations of SN 2005hk and SN 2008A, typical members of the Type Iax class of supernovae (SNe). Here we focus on late-time observations, where these objects deviate ... More