Search Publications
A Volume-limited Sample of Ultracool Dwarfs. II. The Substellar Age and Mass Functions in the Solar Neighborhood
Magnier, Eugene A.; Dupuy, Trent J.; Liu, Michael C. +2 more
We present the most precise constraints to date for the mass and age distributions of single ultracool dwarfs in the solar neighborhood, based on an updated volume-limited sample of 504 L, T, and Y dwarfs within 25 pc. We develop a Monte Carlo approach using the $\langle V/{V}_{\max }\rangle $ statistic to correct for incompleteness and obtain a s…
The Extremely Metal-rich Knot of Stars at the Heart of the Galaxy
Pillepich, Annalisa; Laporte, Chervin F. P.; Rix, Hans-Walter +15 more
We show with Gaia XP spectroscopy that extremely metal-rich (EMR) stars in the Milky Way ([M/H]XP ≳ 0.5) are largely confined to a tight "knot" at the center of the Galaxy. This EMR knot is round in projection, has a fairly abrupt edge near R GC,proj ∼ 1.5 kpc, and is a dynamically hot system. This central knot also contains …
A Deficit of Massive White Dwarfs in Gaia Astrometric Binaries
Hallakoun, Na'ama; Toonen, Silvia; Mazeh, Tsevi +2 more
The third data release of Gaia introduced a large catalog of astrometric binaries, out of which about 3200 are likely main-sequence stars with a white dwarf (WD) companion. These binaries are typically found with orbital separations of ∼1 au, a separation range that was largely unexplored due to observational challenges. Such systems are likely to…
TOI-4201: An Early M Dwarf Hosting a Massive Transiting Jupiter Stretching Theories of Core Accretion
Butler, R. Paul; Mahadevan, Suvrath; Wright, Jason T. +27 more
We confirm TOI-4201 b as a transiting Jovian-mass planet orbiting an early M dwarf discovered by the Transiting Exoplanet Survey Satellite. Using ground-based photometry and precise radial velocities from NEID and the Planet Finder Spectrograph, we measure a planet mass of ${2.59}_{-0.06}^{+0.07}$ M J, making this one of the most massiv…
Was There a 3.5 keV Line?
Safdi, Benjamin R.; Foster, Joshua W.; Dessert, Christopher +1 more
The 3.5 keV line is a purported emission line observed in galaxies, galaxy clusters, and the Milky Way whose origin is inconsistent with known atomic transitions and has previously been suggested to arise from dark matter decay. We systematically reexamine the bulk of the evidence for the 3.5 keV line, attempting to reproduce six previous analyses…
A JWST/MIRI and NIRCam Analysis of the Young Stellar Object Population in the Spitzer I Region of NGC 6822
Temim, Tea; Hirschauer, Alec S.; Boyer, Martha L. +8 more
We present an imaging survey of the Spitzer I star-forming region in NGC 6822 conducted with the NIRCam and MIRI instruments on board JWST. Located at a distance of 490 kpc, NGC 6822 is the nearest non-interacting low-metallicity (∼0.2 Z ⊙) dwarf galaxy. It hosts some of the brightest known H II regions in the local universe, including …
[X/Fe] Marks the Spot: Mapping Chemical Azimuthal Variations in the Galactic Disk with APOGEE
Laporte, Chervin F. P.; Price-Whelan, Adrian M.; Horta, Danny +4 more
Chemical cartography of the Galactic disk provides insights into its structure and assembly history over cosmic time. In this work, we use chemical cartography to explore chemical gradients and azimuthal substructure in the Milky Way disk with giant stars from Apache Point Observatory Galactic Evolution Experiment (APOGEE) DR17. We confirm the exi…
Magnetic Fields in the Central Molecular Zone Influenced by Feedback and Weakly Correlated with Star Formation
Hasegawa, Tetsuo; Gu, Qilao; Liu, Tie +12 more
Magnetic fields of molecular clouds in the central molecular zone (CMZ) have been relatively under-observed at sub-parsec resolution. Here, we report JCMT/POL2 observations of polarized dust emission in the CMZ, which reveal magnetic field structures in dense gas at ∼0.5 pc resolution. The 11 molecular clouds in our sample include two in the weste…
A 2.9 hr Periodic Radio Transient with an Optical Counterpart
Strader, Jay; Rea, N.; Chomiuk, Laura +12 more
We present a long-period radio transient (GLEAM-X J0704‑37) discovered to have an optical counterpart, consistent with a cool main-sequence star of spectral type M3. The radio periodicity occurs at the longest period yet found, 2.9 hr, and was discovered in archival low-frequency data from the Murchison Widefield Array. High time resolution observ…
The Heavy Metal Survey: Star Formation Constraints and Dynamical Masses of 21 Massive Quiescent Galaxies at z = 1.3–2.3
Barro, Guillermo; Franx, Marijn; van Dokkum, Pieter +14 more
In this paper, we present the Heavy Metal Survey, which obtained ultradeep medium-resolution spectra of 21 massive quiescent galaxies at 1.3 < z < 2.3 with Keck/LRIS and MOSFIRE. With integration times of up to 16 hr per band per galaxy, we observe numerous Balmer and metal absorption lines in atmospheric windows. We successfully derive spec…