Search Publications
Ancient Very Metal-poor Stars Associated with the Galactic Disk in the H3 Survey
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +8 more
Ancient, very metal-poor (VMP) stars offer a window into the earliest epochs of galaxy formation and assembly. We combine data from the H3 Spectroscopic Survey and Gaia to measure metallicities, abundances of α elements, stellar ages, and orbital properties of a sample of 482 VMP ([Fe/H] < -2) stars in order to constrain their origins. This sam…
ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Detection of Extremely High-density Compact Structure of Prestellar Cores and Multiple Substructures Within
Sanhueza, Patricio; Kwon, Woojin; Soam, Archana +38 more
Prestellar cores are self-gravitating dense and cold structures within molecular clouds where future stars are born. They are expected, at the stage of transitioning to the protostellar phase, to harbor centrally concentrated dense (sub)structures that will seed the formation of a new star or the binary/multiple stellar systems. Characterizing thi…
An ALMA Gas-dynamical Mass Measurement of the Supermassive Black Hole in the Local Compact Galaxy UGC 2698
Ho, Luis C.; Gebhardt, Karl; Barth, Aaron J. +9 more
We present 0"14 resolution Atacama Large Millimeter/submillimeter Array (ALMA) CO(2-1) observations of the circumnuclear gas disk in UGC 2698, a local compact galaxy. The disk exhibits regular rotation with projected velocities rising to 450 km s-1 near the galaxy center. We fit gas-dynamical models to the ALMA data cube, assuming the C…
Correction to the Photometric Colors of the Gaia Data Release 2 with the Stellar Color Regression Method
Niu, Zexi; Liu, Jifeng; Yuan, Haibo
The second Gaia data release (DR2) delivers accurate and homogeneous photometry data of the whole sky of an exquisite quality, reaching down to the unprecedented millimagnitude (mmag) level for the G, GRP, and GBP passbands. However, the presence of magnitude-dependent systematic effects at the 10 mmag level limits its power …
Evidence of a Clear Atmosphere for WASP-62b: The Only Known Transiting Gas Giant in the JWST Continuous Viewing Zone
Nikolov, Nikolay; Mikal-Evans, Thomas; Sing, David K. +12 more
Exoplanets with cloud-free, haze-free atmospheres at the pressures probed by transmission spectroscopy represent a valuable opportunity for detailed atmospheric characterization and precise chemical abundance constraints. We present the first optical to infrared (0.3-5 µm) transmission spectrum of the hot Jupiter WASP-62b, measured with Hubb…
Tracing PAH Size in Prominent Nearby Mid-Infrared Environments
Tielens, A. G. G. M.; Peeters, E.; Vacca, W. D. +2 more
We present observations from the First Light Infrared TEst CAMera (FLITECAM) on board the Stratospheric Observatory for Infrared Astronomy, the Spitzer Infrared Array Camera (IRAC), and the Spitzer Infrared Spectrograph SH mode in three well-known photodissociation regions, the reflection nebulae (RNe) NGC 7023 and NGC 2023 and to the southeast of…
Correction to the Photometric Magnitudes of the Gaia Early Data Release 3
Huang, Yang; Niu, Zexi; Yuan, Haibo +4 more
In this Letter, we have carried out an independent validation of the Gaia Early Data Release 3 (EDR3) photometry using approximately 10,000 Landolt standard stars from Clem & Landolt (2013). Using a machine-learning technique, the UBVRI magnitudes are converted into the Gaia magnitudes and colors and then compared to those in the EDR3, with th…
TeV Cosmic-Ray Nucleus Acceleration in Shell-type Supernova Remnants with Hard γ-Ray Spectra
Zhang, Shuinai; Liu, Siming; Zeng, Houdun +1 more
The emission mechanism for hard γ-ray spectra from supernova remnants (SNRs) is still a matter of debate. Recent multiwavelength observations of the TeV source HESS J1912+101 show that it is associated with an SNR with an age of ∼100 kyr, making it unlikely produce the TeV γ-ray emission via leptonic processes. We analyzed Fermi observations of it…
Clumpy Star Formation and AGN Activity in the Dwarf-Dwarf Galaxy Merger Mrk 709
Deller, Adam T.; Stern, Daniel; Reines, Amy E. +2 more
Nearby, low-metallicity dwarf starburst galaxies hosting active galactic nuclei (AGNs) offer the best local analogs to study the early evolution of galaxies and their supermassive black holes (BHs). Here we present a detailed multiwavelength investigation of star formation and BH activity in the low-metallicity dwarf-dwarf galaxy merger Mrk 709. U…
Star Formation Timescales of the Halo Populations from Asteroseismology and Chemical Abundances
Shi, Jianrong; Xiang, Maosheng; Li, Haining +9 more
We combine asteroseismology, optical high-resolution spectroscopy, and kinematic analysis for 26 halo red giant branch stars in the Kepler field in the range of -2.5 < [Fe/H] < -0.6. After applying theoretically motivated corrections to the seismic scaling relations, we obtain an average mass of 0.97 ± 0.03 M⊙ for our sample of ha…