Search Publications
Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys
Beers, Timothy C.; Lee, Young Sun; Placco, Vinicius M. +13 more
We analyze the dynamical properties of ∼1500 very metal-poor (VMP; [Fe/H] ≲ -2.0) halo stars, based primarily on medium-resolution spectroscopic data from the HK and Hamburg/ESO surveys. These data, collected over the past 30 yr, are supplemented by a number of calibration stars and other small samples, along with astrometric information from Gaia…
How to Identify Exoplanet Surfaces Using Atmospheric Trace Species in Hydrogen-dominated Atmospheres
Fortney, Jonathan J.; Moses, Julianne I.; Zhang, Xi +1 more
Sub-Neptunes (Rp ~ 1.25-4 REarth) remain the most commonly detected exoplanets to date. However, it remains difficult for observations to tell whether these intermediate-sized exoplanets have surfaces and where their surfaces are located. Here we propose that the abundances of trace species in the visible atmospheres of these…
ALMA Measures Rapidly Depleted Molecular Gas Reservoirs in Massive Quiescent Galaxies at z ∼ 1.5
Bezanson, Rachel; Brammer, Gabriel; Weiner, Benjamin +6 more
We present Atacama Large Millimeter/submillimeter Array (ALMA) CO(2-1) spectroscopy of six massive (log10 ${M}_{* }$ / ${M}_{\odot }$ > 11.3) quiescent galaxies at z ∼ 1.5. These data represent the largest sample using CO emission to trace molecular gas in quiescent galaxies above z > 1, achieving an average 3σ sensitivity of ${M}…
Quantifying Feedback from Narrow Line Region Outflows in Nearby Active Galaxies. III. Results for the Seyfert 2 Galaxies Markarian 3, Markarian 78, and NGC 1068
Rafelski, Marc; Fischer, Travis C.; Collins, Nicholas R. +9 more
Outflows of ionized gas driven by active galactic nuclei (AGN) may significantly impact the evolution of their host galaxies. However, determining the energetics of these outflows is difficult with spatially unresolved observations that are subject to strong global selection effects. We present part of an ongoing study using Hubble Space Telescope…
Gaia EDR3 Parallax Zero-point Offset Based on W Ursae Majoris-type Eclipsing Binaries
Huang, Yang; Deng, Licai; de Grijs, Richard +3 more
We independently determine the zero-point offset of the Gaia early Data Release-3 (EDR3) parallaxes based on ∼110,000 W Ursae Majoris (EW)-type eclipsing binary systems. EWs cover almost the entire sky and are characterized by a relatively complete coverage in magnitude and color. They are an excellent proxy for Galactic main-sequence stars. We de…
New Horizons Observations of the Cosmic Optical Background
Buratti, Bonnie J.; Singer, Kelsi N.; McKinnon, William B. +27 more
We used existing data from the New Horizons Long-range Reconnaissance Imager (LORRI) to measure the optical-band (0.4 ≲ λ ≲ 0.9 µm) sky brightness within seven high-Galactic latitude fields. The average raw level measured while New Horizons was 42-45 au from the Sun is 33.2 ± 0.5 nW m-2 sr-1. This is ∼10× as dark as the…
The Parallax Zero-point of Gaia Early Data Release 3 from LAMOST Primary Red Clump Stars
Huang, Yang; Beers, Timothy C.; Yuan, Haibo +1 more
We present an independent examination of the parallax zero-point of the Third Gaia Early Data Release (hereafter EDR3), using the LAMOST primary red clump (PRC) stellar sample. A median parallax offset of around 26 µas, slightly larger than that found by examination of distant quasars, is found for both the five- and six-parameter solutions …
The TW Hya Rosetta Stone Project. III. Resolving the Gaseous Thermal Profile of the Disk
Zhang, Ke; Öberg, Karin; Walsh, Catherine +16 more
The thermal structure of protoplanetary disks is a fundamental characteristic of the system that has wide-reaching effects on disk evolution and planet formation. In this study, we constrain the 2D thermal structure of the protoplanetary disk TW Hya structure utilizing images of seven CO lines. This includes new ALMA observations of 12C…
The Magnetic Origin of Solar Campfires
Tiwari, Sanjiv K.; Cheung, Mark C. M.; Berghmans, David +4 more
Solar campfires are fine-scale heating events, recently observed by Extreme Ultraviolet Imager (EUI) on board Solar Orbiter. Here we use EUI 174 Å images, together with EUV images from Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA), and line-of-sight magnetograms from SDO/Helioseismic and Magnetic Imager (HMI) to investigate t…
Evidence of a Dwarf Galaxy Stream Populating the Inner Milky Way Halo
Malhan, Khyati; Ibata, Rodrigo A.; Martin, Nicolas F. +3 more
Stellar streams produced from dwarf galaxies provide direct evidence of the hierarchical formation of the Milky Way. Here, we present the first comprehensive study of the LMS-1 stellar stream, that we detect by searching for wide streams in the Gaia EDR3 data set using the STREAMFINDER algorithm. This stream was recently discovered by Yuan et al. …