arXiv subjects

Kenneth W. Smith

Publications and source records attributed to Kenneth W. Smith.

3 recordsLinked to original sources

arXiv2026

ATLAS100 -- I. A volume-limited sample of supernovae and related transients within 100 Mpc

We present ATLAS100 -- a sample of 1729 supernovae and other explosive optical transients within $\sim 100$ Mpc observed by the ATLAS survey over a span of 5.75 years from 2017 September 21 to 2023 June 21. The volume-limited sample includes transients associated with galaxies with a spectroscopic redshift of $z \leq 0.025$, and spectroscopically classified transients within this redshift threshold where a host redshift was not available in existing catalogues. Our host galaxy list is constructed from aggregating all available galaxy redshift and distance catalogues. We carefully select all transients within a projected radius of 50\,kpc of these hosts. The ATLAS100 transient sample has a host galaxy redshift completeness fraction of $83$ per cent, consistent with expectations for the redshift completeness of local galaxy catalogues. Within this volume, the spectroscopic classifications are 87 per cent complete and we reclassify many ambiguous transients with joint light curve and spectroscopic considerations. Here, we release the catalogue together with compiled, binned and cleaned ATLAS photometry for all transients. We fit the light curve data to derive peak luminosity and characteristic timescales. We explore the sample characteristics, demographics and discuss completeness and purity of the sample.

astro-ph.HE↗

arXiv2019

Signatures of Circumstellar Interaction in the Type IIL Supernova ASASSN-15oz

Hydrogen-rich, core-collapse supernovae are typically divided into four classes: IIP, IIL, IIn, and IIb. In general, interaction with circumstellar material is only considered for Type IIn supernovae. However, recent hydrodynamic modeling of IIP and IIL supernovae requires circumstellar material to reproduce their early light curves. In this scenario, IIL supernovae experience large amounts of mass loss before exploding. We test this hypothesis on ASASSN-15oz, a Type IIL supernova. With extensive follow-up in the X- ray, UV, optical, IR, and radio we present our search for signs of interaction, and the mass-loss history indicated by their detection. We find evidence of short-lived intense mass-loss just prior to explosion from light curve modeling, amounting in 1.5 M$_{\odot}$ of material within 1800 R$_{\odot}$ of the progenitor. We also detect the supernova in the radio, indicating mass-loss rates of $10^{-6}-10^{-7}$ M$_{\odot}$ yr$^{-1}$ prior to the extreme mass-loss period. Our failure to detect the supernova in the X-ray and the lack of narrow emission lines in the UV, optical, and NIR do not contradict this picture and place an upper limit on the mass-loss rate outside the extreme period of $<10^{-4}$ M$_{\odot}$ yr$^{-1}$. This paper highlights the importance gathering comprehensive data on more Type II supernovae to enable detailed modeling of the progenitor and supernova which can elucidate their mass-loss histories and envelope structures and thus inform stellar evolution models.

astro-ph.SR↗

arXiv2017

A dwarf planet class object in the 21:5 resonance with Neptune

We report the discovery of a $H_r = 3.4\pm0.1$ dwarf planet candidate by the Pan-STARRS Outer Solar System Survey. 2010 JO$_{179}$ is red with $(g-r)=0.88 \pm 0.21$, roughly round, and slowly rotating, with a period of $30.6$ hr. Estimates of its albedo imply a diameter of 600--900~km. Observations sampling the span between 2005--2016 provide an exceptionally well-determined orbit for 2010 JO$_{179}$, with a semi-major axis of $78.307\pm0.009$ au, distant orbits known to this precision are rare. We find that 2010 JO$_{179}$ librates securely within the 21:5 mean-motion resonance with Neptune on hundred-megayear time scales, joining the small but growing set of known distant dwarf planets on metastable resonant orbits. These imply a substantial trans-Neptunian population that shifts between stability in high-order resonances, the detached population, and the eroding population of the scattering disk.

astro-ph.EP↗