Search Publications
The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. VI. Insights from Radiative Transfer Modeling
Sheehan, Patrick D.; Megeath, S. Thomas; Looney, Leslie W. +1 more
We present Markov Chain Monte Carlo radiative transfer modeling of a joint ALMA 345 GHz and spectral energy distribution data set for a sample of 97 protostellar disks from the VLA and ALMA Nascent Disk and Multiplicity Survey of Orion Protostars. From this modeling, we derive disk and envelope properties for each protostar, allowing us to examine…
SALT3-NIR: Taking the Open-source Type Ia Supernova Model to Longer Wavelengths for Next-generation Cosmological Measurements
Pérez-Fournon, I.; Fox, O. D.; Poidevin, F. +32 more
A large fraction of Type Ia supernova (SN Ia) observations over the next decade will be in the near-infrared (NIR), at wavelengths beyond the reach of the current standard light-curve model for SN Ia cosmology, SALT3 (~2800-8700 Å central filter wavelength). To harness this new SN Ia sample and reduce future light-curve standardization systematic …
Galactic Kinematics and Observed Flare Rates of a Volume-complete Sample of Mid-to-late M Dwarfs: Constraints on the History of the Stellar Radiation Environment of Planets Orbiting Low-mass Stars
Winters, Jennifer G.; Medina, Amber A.; Irwin, Jonathan M. +1 more
We present a study of the relationship between Galactic kinematics, flare rates, chromospheric activity, and rotation periods for a volume-complete, nearly all-sky sample of 219 single stars within 15 pc and with masses between 0.1 and 0.3 M ⊙ observed during the primary mission of TESS. We find all stars consistent with a common value …
On the Spectral Evolution of Hot White Dwarf Stars. II. Time-dependent Simulations of Element Transport in Evolving White Dwarfs with STELUM
Bergeron, P.; Blouin, S.; Bédard, A. +1 more
White dwarf stars are subject to various element transport mechanisms that can cause their surface composition to change radically as they cool, a phenomenon known as spectral evolution. In this paper, we undertake a comprehensive theoretical investigation of the spectral evolution of white dwarfs. First, we introduce STELUM, a new implementation …
Resolving the Core of R136 in the Optical
Rubio, Monica; Horch, Elliott P.; Vink, Jorick S. +4 more
The sharpest optical images of the R136 cluster in the Large Magellanic Cloud are presented, allowing us for the first time to resolve members of the central core, including R136a1, the most-massive star known. These data were taken using the Gemini speckle imager Zorro in medium-band filters with effective wavelengths similar to BVRI achieving an…
A New Flaring Black Widow Candidate and Demographics of Black Widow Millisecond Pulsars in the Galactic Field
Strader, Jay; Ray, Paul S.; Kerr, Matthew +4 more
We present the discovery of a new optical/X-ray source likely associated with the Fermi γ-ray source 4FGL J1408.6-2917. Its high-amplitude periodic optical variability, large spectroscopic radial-velocity semiamplitude, evidence for optical emission lines and flaring, and X-ray properties together imply the source is probably a new black widow mil…
Tidal Distortions in NGC1052-DF2 and NGC1052-DF4: Independent Evidence for a Lack of Dark Matter
van Dokkum, Pieter; Abraham, Roberto; Pasha, Imad +11 more
Two ultra-diffuse galaxies in the same group, NGC1052-DF2 and NGC1052-DF4, have been found to have little or no dark matter and to host unusually luminous globular cluster populations. Such low-mass diffuse objects in a group environment are easily disrupted and are expected to show evidence of tidal distortions. In this work, we present deep new …
Slow Star Formation in the Milky Way: Theory Meets Observations
Ostriker, Eve C.; Evans, Neal J.; Kim, Jeong-Gyu
The observed star formation rate of the Milky Way can be explained by applying a metallicity-dependent factor to convert CO luminosity to molecular gas mass and a star formation efficiency per freefall time that depends on the virial parameter of a molecular cloud. These procedures also predict the trend of star formation rate surface density with…
Post-starburst Galaxies in the Centers of Intermediate-redshift Clusters
Richard, Johan; Mingozzi, Matilde; Fritz, Jacopo +17 more
We present results from MUSE spatially resolved spectroscopy of 21 post-starburst galaxies in the centers of eight clusters from z ~ 0.3 to z ~ 0.4. We measure spatially resolved star formation histories (SFHs), the time since quenching (t Q ), and the fraction of stellar mass assembled in the past 1.5 Gyr (µ 1.5). The…
Effects of UV Stellar Spectral Uncertainty on the Chemistry of Terrestrial Atmospheres
Youngblood, Allison; Kempton, Eliza M. -R.; Arney, Giada +2 more
The upcoming deployment of the James Webb Space Telescope will dramatically advance our ability to characterize exoplanet atmospheres, both in terms of precision and sensitivity to smaller and cooler planets. Disequilibrium chemical processes dominate these cooler atmospheres, requiring accurate photochemical modeling of such environments. The hos…