arXiv subjects

Laura B. Chomiuk

Publications and source records attributed to Laura B. Chomiuk.

2 recordsLinked to original sources

arXiv2026

A Multiwavelength Inventory for the Local Group L-band Survey I: Atlas and Radial Profiles of Local Group Galaxies

Resolving atomic gas at $\lesssim100$ pc physical resolution is currently feasible only for the very nearest galaxies. We combine 120 pc resolution HI data using the Karl G. Jansky Very Large Array (VLA) from the first data release of the Local Group L-Band Survey (LGLBS) with uniformly processed infrared, ultraviolet, H$α$, and CO maps. We analyze the radial profiles of gas, stars, and recent star formation for six local galaxies: M31, M33, IC 10, IC 1613, NGC 6822, and WLM. Across the sample, atomic-gas disks are the most extended component, reaching $r_{\rm HI}=2.8$-$5.8$ kpc in the dwarfs and $13$-$26$ kpc in M33 and M31. Azimuthally averaged $Σ_{\rm HI}$ profiles are often flat or only slowly declining compared to the steeper decline of $Σ_{\star}$ and $Σ_\mathrm{SFR}$, with outer HI scale lengths of $l_{\rm HI}^{\rm outer}\approx1.0$-$8.5$ kpc. The mass-weighted HI surface densities on 120 pc scale generally exceed the azimuthally averaged values by 10-70%, showing that localized high-column-density atomic structures persist even where azimuthally averaged profiles appear smooth. Atomic-gas depletion times rise from $τ_{\rm dep}^{\rm atom}\approx0.8$-17 Gyr within the stellar half-mass radius to 10s-100 Gyr in the outer disks. Molecular depletion times are shorter. We provide a public release of these multi-wavelength data, which provide a valuable reference for the LGLBS targets and also form the basis for a companion paper that relates star formation, gas phases, and midplane pressure on 120 pc scales.

astro-ph.GA↗

arXiv2015

A New Model for the Radio Emission from SN 1994I and an Associated Search for Radio Transients in M51

We revisit the exquisite archival radio data for the Type Ic supernova SN 1994I and present a revised model for the SN radio emission and a pilot study that aims to constrain the rate of C-band radio transients within the face-on host galaxy, M51 (NGC 5194). We find that the temporal and spectral evolution of the SN\,1994I radio emission are well fit by a synchrotron self-absorption model and use this to estimate physical parameters. We compute a pre-explosion mass loss rate of $\dot{M}=3.0 \times 10^{-5} M_{\odot}$ yr$^{-1}$ for the progenitor, consistent with those observed from galactic Wolf-Rayet stars. Our model makes different assumptions for the dynamical model for the shockwave interaction than the model previously published by \cite{weil11}, but our $\dot{M}$ is consistent with theirs to within errors and assumptions. Drawing from a subset of the archival radio observations from the Very Large Array collected for the monitoring of SN\,1994I, we conduct a pilot study to search for previously-unidentified transients. Data were primarily taken at a frequency of 4.9 GHz and are logarithmic in cadence, enabling sensitivity to transients with variability timescales ranging from days to months. We find no new transient detections in 31 epochs of data, allowing us to place a $2σ$ upper limit of 17 deg$^{-2}$ for the source density of radio transients above 0.5 mJy ($L\gtrsim4\times10^{25}$ erg s$^{-1}$ Hz$^{-1}$ at the distance of M51). This study highlights the feasibility of utilizing archival high-cadence radio studies of supernova host galaxies to place constraints on the radio transient rate as a function of luminosity in the local Universe.

astro-ph.HE↗