Search Publications
Identifying Tidal Disruption Events with an Expansion of the FLEET Machine-learning Algorithm
Villar, V. Ashley; van Velzen, Sjoert; Gezari, Suvi +5 more
We present an expansion of FLEET, a machine-learning algorithm optimized to select transients that are most likely tidal disruption events (TDEs). FLEET is based on a random forest algorithm trained on both the light curves and host galaxy information of 4779 spectroscopically classified transients. We find that for transients with a probability o…
A 1.3% Distance to M33 from Hubble Space Telescope Cepheid Photometry
Casertano, Stefano; Williams, Benjamin F.; Li, Siyang +7 more
We present a low-dispersion period-luminosity relation (PL) based on 154 Cepheids in Messier 33 (M33) with Hubble Space Telescope (HST) photometry from the PHATTER survey. Using high-quality ground-based light curves, we recover Cepheid phases and amplitudes for multi-epoch HST data and we perform template fitting to derive intensity-averaged mean…
DELVE 6: An Ancient, Ultra-faint Star Cluster on the Outskirts of the Magellanic Clouds
Geha, M.; James, D. J.; Kuropatkin, N. +24 more
We present the discovery of DELVE 6, an ultra-faint stellar system identified in the second data release of the DECam Local Volume Exploration (DELVE) survey. Based on a maximum-likelihood fit to its structure and stellar population, we find that DELVE 6 is an old (τ > 9.8 Gyr at 95% confidence) and metal-poor ([Fe/H] < -1.17 dex at 95% conf…
The Distribution of Metallicities in the Local Galactic Interstellar Medium
Jenkins, Edward B.; Savage, Blair D.; Shull, J. Michael +3 more
In this investigation, we present an analysis of the metallicity distribution that pertains to neutral gas in the local Galactic interstellar medium (ISM). We derive relative ISM metallicities for a sample of 84 sight lines probing diffuse atomic and molecular gas within 4 kpc of the Sun. Our analysis is based in large part on column density measu…
Hubble Constant Measurement from Three Large-separation Quasars Strongly Lensed by Galaxy Clusters
Mahler, Guillaume; Rigby, Jane R.; Bayliss, Matthew +5 more
Tension between cosmic microwave background-based and distance ladder-based determinations of the Hubble constant H 0 motivates the pursuit of independent methods that are not subject to the same systematic effects. A promising alternative, proposed by Refsdal in 1964, relies on the inverse scaling of H 0 with the delay betwe…
Constraints on the Dust Size Distributions in the HD 163296 Disk from the Difference of the Apparent Dust Ring Widths between Two ALMA Bands
Kataoka, Akimasa; Doi, Kiyoaki
The dust size in protoplanetary disks is a crucial parameter for understanding planet formation, while the observational constraints on dust size distribution have large uncertainties. In this study, we present a new method to constrain the dust size distribution from the dust spatial distribution, utilizing the fact that larger dust grains are mo…
Dependence of Cosmological Constraints on Gray Photometric Zero-point Uncertainties of Supernova Surveys
Riess, Adam G.; Stubbs, Christopher W.; Brout, Dillon +2 more
Type Ia supernova (SN) measurements of the Hubble constant, H 0; cosmic mass density, Ω M ; and dark energy equation-of-state parameter, w, rely on heterogeneous SN surveys across three decades of observation. These distinct surveys may have undiagnosed, relative photometric zero-point errors. We determine the sensitivities o…
Investigating the Narrow-line Region Dynamics in Nearby Active Galaxies
Fischer, Travis C.; Crenshaw, D. Michael; Schmitt, Henrique R. +7 more
We present dynamical models of the narrow-line region (NLR) outflows in the nearby Seyfert galaxies Mrk 3, Mrk 78, NGC 1068, and NGC 4151 using observations from the Hubble Space Telescope and Apache Point Observatory. We employ long-slit spectroscopy to map the spatially resolved outflow and rotational velocities of the ionized gas. We also perfo…
Multiphase Gas Interactions on Subarcsec Scales in the Shocked Intergalactic Medium of Stephan's Quintet with JWST and ALMA
Togi, Aditya; Duc, P. -A.; Appleton, P. N. +12 more
We combine James Webb Space Telescope (JWST) and Hubble Space Telescope imaging with Atacama Large Millimeter Array CO(2-1) spectroscopy to study the highly turbulent multiphase intergalactic medium (IGM) in Stephan's Quintet on 25-150 pc scales. Previous Spitzer observations revealed luminous H2 line cooling across a 45 kpc-long filame…
Beyond Spectroscopy. II. Stellar Parameters for over 20 Million Stars in the Northern Sky from SAGES DR1 and Gaia DR3
Tan, Ke-Feng; Zhao, Gang; Fan, Zhou +18 more
We present precise photometric estimates of stellar parameters, including effective temperature, metallicity, luminosity classification, distance, and stellar age, for nearly 26 million stars using the methodology developed in the first paper of this series, based on the stellar colors from the Stellar Abundances and Galactic Evolution Survey (SAG…