Search Publications
Dynamical Relics of the Ancient Galactic Halo
Zhao, Gang; Myeong, G. C.; Evans, N. W. +11 more
We search for dynamical substructures in the LAMOST DR3 very metal-poor (VMP) star catalog. After cross-matching with Gaia DR2, there are ∼3300 VMP stars with available high-quality astrometric information that have halo-like kinematics. We apply a method based on the self-organizing map StarGO to find groups clustered in the 4D space of orbital e…
The VLA-COSMOS 3 GHz Large Project: Evolution of Specific Star Formation Rates out to z ∼ 5
Zamorani, Giovanni; Schinnerer, Eva; Liu, Daizhong +17 more
We provide a coherent, uniform measurement of the evolution of the logarithmic star formation rate (SFR)-stellar mass (M*) relation, called the main sequence (MS) of star-forming galaxies , for star-forming and all galaxies out to $z\sim 5$ . We measure the MS using mean stacks of 3 GHz radio-continuum images to derive average SFRs for …
A New Census of the 0.2 < z < 3.0 Universe. I. The Stellar Mass Function
Franx, Marijn; van Dokkum, Pieter; Conroy, Charlie +3 more
There has been a long-standing factor-of-two tension between the observed star formation rate density and the observed stellar mass buildup after z ∼ 2. Recently, we have proposed that sophisticated panchromatic SED models can resolve this tension, as these methods infer systematically higher masses and lower star formation rates than standard app…
A White Dwarf with Transiting Circumstellar Material Far outside the Roche Limit
Hermes, J. J.; Montgomery, M. H.; Winget, D. E. +9 more
We report the discovery of a white dwarf exhibiting deep, irregularly shaped transits, indicative of circumstellar planetary debris. Using Zwicky Transient Facility DR2 photometry of ZTF J013906.17+524536.89 and follow-up observations from the Las Cumbres Observatory, we identify multiple transit events that recur every ≈107.2 days, much longer th…
The Lazy Giants: APOGEE Abundances Reveal Low Star Formation Efficiencies in the Magellanic Clouds
Cohen, Roger E.; Cunha, Katia; Smith, Verne V. +28 more
We report the first APOGEE metallicities and α-element abundances measured for 3600 red giant stars spanning a large radial range of both the Large (LMC) and Small Magellanic Clouds, the largest Milky Way (MW) dwarf galaxies. Our sample is an order of magnitude larger than that of previous studies and extends to much larger radial distances. These…
The Complete Redshift Distribution of Dusty Star-forming Galaxies from the SPT-SZ Survey
Béthermin, M.; Weiss, A.; Greve, T. R. +21 more
The South Pole Telescope (SPT) has systematically identified 81 high-redshift, strongly gravitationally lensed, dusty star-forming galaxies (DSFGs) in a 2500 square degree cosmological millimeter-wave survey. We present the final spectroscopic redshift survey of this flux-limited (S870 µm > 25 mJy) sample, initially selected at…
Timing the Early Assembly of the Milky Way with the H3 Survey
van Dokkum, Pieter; Conroy, Charlie; Ting, Yuan-Sen +7 more
The archeological record of stars in the Milky Way opens a uniquely detailed window into the early formation and assembly of galaxies. Here we use 11,000 main-sequence turn-off stars with well-measured ages, $[\mathrm{Fe}/{\rm{H}}]$ , $[\alpha /\mathrm{Fe}]$ , and orbits from the H3 Survey and Gaia to time the major events in the early Galaxy. Loc…
Close Binary Companions to APOGEE DR16 Stars: 20,000 Binary-star Systems Across the Color-Magnitude Diagram
Green, Paul J.; Hogg, David W.; Majewski, Steven R. +21 more
Many problems in contemporary astrophysics—from understanding the formation of black holes to untangling the chemical evolution of galaxies—rely on knowledge about binary stars. This, in turn, depends on the discovery and characterization of binary companions for large numbers of different kinds of stars in different chemical and dynamical environ…
The Sloan Digital Sky Survey Reverberation Mapping Project: Estimating Masses of Black Holes in Quasars with Single-epoch Spectroscopy
Brandt, W. N.; Shen, Yue; Peterson, Bradley M. +19 more
It is well known that reverberation mapping of active galactic nuclei (AGNs) reveals a relationship between AGN luminosity and the size of the broad-line region, and that use of this relationship, combined with the Doppler width of the broad emission line, enables an estimate of the mass of the black hole at the center of the active nucleus based …
The MOSDEF Survey: The Variation of the Dust Attenuation Curve with Metallicity
Siana, Brian; Azadi, Mojegan; Shivaei, Irene +14 more
We derive a UV-optical stellar dust attenuation curve of galaxies at z = 1.4-2.6 as a function of gas-phase metallicity. We use a sample of 218 star-forming galaxies, excluding those with very young or heavily obscured star formation, from the MOSFIRE Deep Evolution Field survey with Hα, Hβ, and [N II]λ 6585 spectroscopic measurements. We constrai…