Search Publications
The Brown Dwarf Kinematics Project (BDKP). V. Radial and Rotational Velocities of T Dwarfs from Keck/NIRSPEC High-resolution Spectroscopy
Gelino, Christopher R.; Burgasser, Adam J.; Faherty, Jacqueline K. +7 more
We report multiepoch radial velocities, rotational velocities, and atmospheric parameters for 37 T-type brown dwarfs observed with Keck/NIRSPEC. Using a Markov Chain Monte Carlo forward-modeling method, we achieve median precisions of 0.5 and 0.9 km s-1 for radial and rotational velocities, respectively. All of the T dwarfs in our sampl…
TESS Observations of Cepheid Stars: First Light Results
Smolec, R.; Szabados, L.; Christensen-Dalsgaard, J. +33 more
We present the first analysis of Cepheid stars observed by the TESS space mission in Sectors 1-5. Our sample consists of 25 pulsators: ten fundamental mode, three overtone and two double-mode classical Cepheids, plus three type II and seven anomalous Cepheids. The targets were chosen from fields with different stellar densities, both from the Gala…
Stellar Metallicities from SkyMapper Photometry. II. Precise Photometric Metallicities of ∼280,000 Giant Stars with [Fe/H] < -0.75 in the Milky Way
Frebel, Anna; Mardini, Mohammad K.; Chiti, Anirudh +3 more
The Milky Way's metal-poor stars are nearby ancient objects that are used to study early chemical evolution and the assembly and structure of the Milky Way. Here we present reliable metallicities of ∼280,000 stars with -3.75 ≲ [Fe/H] ≲ -0.75 down to g = 17 derived using metallicity-sensitive photometry from the second data release of the SkyMapper…
The Magellan-TESS Survey. I. Survey Description and Midsurvey Results
Butler, R. Paul; Vanderburg, Andrew; Latham, David W. +67 more
Kepler revealed that roughly one-third of Sunlike stars host planets orbiting within 100 days and between the size of Earth and Neptune. How do these planets form, what are they made of, and do they represent a continuous population or multiple populations? To help address these questions, we began the Magellan-TESS Survey (MTS), which uses Magell…
Infrared Surface Brightness Fluctuation Distances for MASSIVE and Type Ia Supernova Host Galaxies
Ma, Chung-Pei; Greene, Jenny E.; Garnavich, Peter M. +9 more
We measured high-quality surface brightness fluctuation (SBF) distances for a sample of 63 massive early-type galaxies using the WFC3/IR camera on the Hubble Space Telescope. The median uncertainty on the SBF distance measurements is 0.085 mag, or 3.9% in distance. Achieving this precision at distances of 50-100 Mpc required significant improvemen…
591 High-velocity Stars in the Galactic Halo Selected from LAMOST DR7 and Gaia DR2
Zhao, Gang; Xiang, Maosheng; Ting, Yuan-Sen +14 more
In this paper, we report 591 high-velocity star candidates (HiVelSCs) selected from over 10 million spectra of Data Release 7 (DR7) of the Large Sky Area Multi-object Fiber Spectroscopic Telescope and the second Gaia data release, with three-dimensional velocities in the Galactic rest frame larger than 445 km s-1. We show that at least …
Molecules with ALMA at Planet-forming Scales. XX. The Massive Disk around GM Aurigae
Zhang, Ke; Wilner, David J.; Ménard, François +25 more
Gas mass remains one of the most difficult protoplanetary disk properties to constrain. With much of the protoplanetary disk too cold for the main gas constituent, H2, to emit, alternative tracers such as dust, CO, or the H2 isotopologue HD are used. However, relying on disk mass measurements from any single tracer requires a…
The XMM-SERVS Survey: XMM-Newton Point-source Catalogs for the W-CDF-S and ELAIS-S1 Fields
Yang, Guang; Trump, Jonathan R.; Brandt, W. N. +30 more
We present the X-ray point-source catalogs in two of the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS) fields, W-CDF-S (4.6 deg2) and ELAIS-S1 (3.2 deg2), aiming to fill the gap between deep pencil-beam X-ray surveys and shallow X-ray surveys over large areas. The W-CDF-S and ELAIS-S1 regions were targete…
Massive Compact Disks around FU Orionis-type Young Eruptive Stars Revealed by ALMA
Kudo, T.; Liu, H. B.; Ábrahám, P. +14 more
The FU Orionis-type objects (FUors) are low-mass pre-main-sequence stars undergoing a temporary but significant increase of mass accretion rate from the circumstellar disk onto the protostar. It is not yet clear what triggers the accretion bursts and whether the disks of FUors are in any way different from the disks of nonbursting young stellar ob…
Hot Subdwarf Atmospheric Parameters, Kinematics, and Origins Based on 1587 Hot Subdwarf Stars Observed in Gaia DR2 and LAMOST DR7
Han, Zhanwen; Luo, Yangping; Németh, Péter +2 more
Based on the Gaia DR2 catalog of hot subdwarf star candidates, we identified 1587 hot subdwarf stars with spectra in LAMOST DR7. We present atmospheric parameters for these stars by fitting the LAMOST spectra with TLUSTY/SYNSPEC non-LTE synthetic spectra. Combining LAMOST radial velocities and Gaia Early Data Release 3 (EDR3) parallaxes and proper…