Search Publications
SDSS-IV eBOSS Spectroscopy of X-Ray and WISE AGNs in Stripe 82X: Overview of the Demographics of X-Ray- and Mid-infrared-selected Active Galactic Nuclei
Ananna, Tonima Tasnim; Salvato, Mara; Vivek, M. +5 more
We report the results of a Sloan Digital Sky Survey IV eBOSS program to target X-ray sources and mid-infrared-selected Wide-field Infrared Survey Explorer (WISE) active galactic nucleus (AGN) candidates in a 36.8 deg2 region of Stripe 82. About half this survey (15.6 deg2) covers the largest contiguous portion of the Stripe 8…
The Elusive Majority of Young Moving Groups. I. Young Binaries and Lithium-rich Stars in the Solar Neighborhood
Baranec, Christoph; Law, Nicholas M.; Riddle, Reed +8 more
Young stars in the solar neighborhood serve as nearby probes of stellar evolution and represent promising targets to directly image self-luminous giant planets. We have carried out an all-sky search for late-type (≈K7-M5) stars within 100 pc selected primarily on the basis of activity indicators from the Galaxy Evolution Explorer and ROSAT. Approx…
Infrared Contributions of X-Ray Selected Active Galactic Nuclei in Dusty Star-forming Galaxies
Azadi, Mojegan; Cooray, Asantha; Ma, Jingzhe +3 more
We investigate the infrared (IR) contribution from supermassive black hole activity versus host galaxy emission in the mid- to far-IR spectrum for a large sample of X-ray bright active galactic nuclei (AGN) residing in dusty, star-forming host galaxies. We select 703 AGN with {L}{{X}}={10}42{--}{10}46 erg s-1<…
Detection of a 50° long Trailing Tidal Tail for the Globular Cluster M5
Grillmair, Carl J.
Using photometry and proper motions from Gaia Data Release 2, we detect a 50° long stream of about 70 stars extending westward from the halo globular cluster M5. Based on the similarities in distance, proper motions, inferred color-magnitude distribution, and trajectory, we identify this stream as the trailing tidal tail of M5. While the surface d…
Episodically Active Asteroid 6478 Gault
Kotulla, Ralf; Jewitt, David; Rajagopal, Jayadev +4 more
We present imaging and spectroscopic observations of 6478 Gault, a ∼6 km diameter inner main-belt asteroid currently exhibiting strong, comet-like characteristics. Three distinct tails indicate that ultra-slow dust (ejection speed 0.15 ± 0.05 m s-1) was emitted from Gault in separate episodes beginning UT 2018 October 28 ± 5 (Tail A), U…
Discovery of a New Stellar Subpopulation Residing in the (Inner) Stellar Halo of the Milky Way
Beers, Timothy C.; Placco, Vinicius M.; Robin, Annie C. +8 more
We report the discovery of a unique collection of metal-poor giant stars that exhibit anomalously high levels of 28Si, clearly above typical Galactic levels. Our sample spans a narrow range of metallicities, peaking at -1.07 ± 0.06, and exhibits abundance ratios of [Si, Al/Fe] that are as extreme as those observed in Galactic globular c…
Short-duration Stellar Flares in GALEX Data
Brasseur, C. E.; Osten, Rachel A.; Fleming, Scott W.
We report on a population of short-duration near-ultraviolet (NUV) flares in stars observed by the Kepler and Galaxy Evolution Explorer (GALEX) missions. We analyzed the NUV light curves of 34,276 stars observed from 2009 to 2013 by both the GALEX (NUV) and Kepler (optical) space missions with the eventual goal of investigating multiwavelength fla…
Geometry, Kinematics, and Heliospheric Impact of a Large CME-driven Shock in 2017 September
Liu, Ying D.; Zhao, Xiaowei; Zhu, Bei
A powerful coronal mass ejection (CME) occurred on 2017 September 10 near the end of the declining phase of the historically weak solar cycle 24. We obtain new insights concerning the geometry and kinematics of CME-driven shocks in relation to their heliospheric impacts from the optimal, multispacecraft observations of the eruption. The shock, whi…
Thermal Infrared Imaging of MWC 758 with the Large Binocular Telescope: Planetary-driven Spiral Arms?
Dong, Ruobing; Wagner, Kevin; Ertel, Steve +5 more
Theoretical studies suggest that a giant planet around the young star MWC 758 could be responsible for driving the spiral features in its circumstellar disk. Here, we present a deep imaging campaign with the Large Binocular Telescope with the primary goal of imaging the predicted planet. We present images of the disk in two epochs in the L‧ filter…
Star Formation Histories of the LEGUS Dwarf Galaxies. III. The Nonbursty Nature of 23 Star-forming Dwarf Galaxies
Cignoni, M.; Tosi, M.; Sabbi, E. +15 more
We derive the recent star formation histories (SFHs) of 23 active dwarf galaxies using Hubble Space Telescope observations from the Legacy Extragalactic UV Survey. We apply a color-magnitude diagram (CMD) fitting technique using two independent sets of stellar models, PARSEC-COLIBRI and MIST. Despite the nonnegligible recent activity, none of the …