Search Publications
Discovery of Tidal Tails in Disrupting Open Clusters: Coma Berenices and a Neighbor Stellar Group
Lin, Chien-Cheng; Tang, Shih-Yun; Chen, W. P. +6 more
We report the discovery of tidal structures around the intermediate-aged (∼700-800 Myr), nearby (∼85 pc) star cluster Coma Berenices. The spatial and kinematic grouping of stars is determined with the Gaia DR2 parallax and proper motion data, by a clustering analysis tool, STARGO, to map 5D parameters (X, Y, Z, {µ }α \cos δ ,{&mic…
Under the FIRElight: Stellar Tracers of the Local Dark Matter Velocity Distribution in the Milky Way
Faucher-Giguère, Claude-André; Hopkins, Philip F.; Sanderson, Robyn +5 more
The Gaia era opens new possibilities for discovering the remnants of disrupted satellite galaxies in the solar neighborhood. If the population of local accreted stars is correlated with the dark matter sourced by the same mergers, one can then map the dark matter distribution directly. Using two cosmological zoom-in hydrodynamic simulations of Mil…
Toward Precision Tests of General Relativity with Black Hole X-Ray Reflection Spectroscopy
Tripathi, Ashutosh; Abdikamalov, Askar B.; Ayzenberg, Dimitry +5 more
Astrophysical black hole systems are the ideal laboratories for testing Einstein’s theory of gravity in the strong field regime. We have recently developed a framework that uses the reflection spectrum of black hole systems to perform precision tests of general relativity by testing the Kerr black hole hypothesis. In this paper, we analyze XMM-New…
Hybrid-kinetic Simulations of Ion Heating in Alfvénic Turbulence
Quataert, Eliot; Chandran, Benjamin D. G.; Kunz, Matthew W. +1 more
We present three-dimensional, hybrid-kinetic numerical simulations of driven Alfvén-wave turbulence of relevance to the collisionless near-Earth solar wind. Special attention is paid to the spectral transition that occurs near the ion-Larmor scale and to the origins of preferential perpendicular ion heating and of nonthermal wings in the parallel …
The Nearby, Young, Argus Association: Membership, Age, and Dusty Debris Disks
Zuckerman, B.
The reality of a field Argus Association has been doubted in some papers in the literature. We apply Gaia DR2 data to stars previously suggested to be Argus members and conclude that a true association exists with age 40-50 Myr and containing many stars within 100 pc of Earth; β Leo and 49 Cet are two especially interesting members. Based on youth…
A Sequoia in the Garden: FSR 1758—Dwarf Galaxy or Giant Globular Cluster?
Monachesi, Antonela; Gómez, Facundo A.; Minniti, Dante +5 more
We present the physical characterization of FSR 1758, a new large, massive object very recently discovered in the Galactic Bulge. The combination of optical data from the 2nd Gaia Data Release and the DECam Plane Survey and near-IR data from the VISTA Variables in the Vía Láctea Extended Survey led to a clean sample of likely members. Based on thi…
A Survey of C2H, HCN, and C18O in Protoplanetary Disks
Bergin, Edwin A.; Bergner, Jennifer B.; Loomis, Ryan A. +3 more
Molecular lines observed toward protoplanetary disks carry information about physical and chemical processes associated with planet formation. We present ALMA Band 6 observations of C2H, HCN, and C18O in a sample of 14 disks spanning a range of ages, stellar luminosities, and stellar masses. Using C2H and HCN hyper…
The Apache Point Observatory Catalog of Optical Diffuse Interstellar Bands
Zhao, Gang; York, Donald G.; Welty, Daniel E. +7 more
Aiming for a new and more comprehensive DIB catalog between 4000 and 9000 Å, we revisited the Atlas Catalog based on the observations of HD 183143 and HD 204827. Twenty-five medium to highly reddened sight lines were selected, sampling a variety of spectral types of the background star and the interstellar environments. The median signal-to-noise …
TESS Delivers Its First Earth-sized Planet and a Warm Sub-Neptune
Butler, R. Paul; Vanderburg, Andrew; Latham, David W. +48 more
The future of exoplanet science is bright, as Transiting Exoplanet Survey Satellite (TESS) once again demonstrates with the discovery of its longest-period confirmed planet to date. We hereby present HD 21749b (TOI 186.01), a sub-Neptune in a 36 day orbit around a bright (V = 8.1) nearby (16 pc) K4.5 dwarf. TESS measures HD 21749b to be {2.61}
Sulfur Chemistry in Protoplanetary Disks: CS and H2CS
Bergner, Jennifer B.; Le Gal, Romane; Loomis, Ryan A. +2 more
The nature and abundance of sulfur chemistry in protoplanetary disks (PPDs) may impact the sulfur inventory on young planets and therefore their habitability. PPDs also offer an interesting test bed for sulfur chemistry models, since each disk shows a diverse set of environments. In this context, we present new sulfur molecule observations in PPDs…