Search Publications
Old, Metal-poor Extreme Velocity Stars in the Solar Neighborhood
Bell, Eric F.; Hattori, Kohei; Roederer, Ian U. +1 more
We report the discovery of 30 stars with extreme space velocities (≳480 {km} {{{s}}}-1) in the Gaia-DR2 archive. These stars are a subset of 1743 stars with high-precision parallax, large tangential velocity (v tan > 300 {km} {{{s}}}-1), and measured line-of-sight velocity in DR2. By tracing the orbits of the st…
Streamer-blowout Coronal Mass Ejections: Their Properties and Relation to the Coronal Magnetic Field Structure
Vourlidas, Angelos; Webb, David F.
We present a comprehensive analysis of a particular class of coronal mass ejection (CME) event called streamer-blowout CMEs (SBOs). The events are characterized by a gradual swelling of the overlying streamer, lasting hours to days, followed by a slow, wide CME, generally exhibiting a three-part structure, which leaves the streamer significantly d…
Polar Dust, Nuclear Obscuration, and IR SED Diversity in Type-1 AGNs
Lyu, Jianwei; Rieke, George H.
Despite the hypothesized similar face-on viewing angles, the infrared emission of type-1 active galactic nuclei (AGNs) has diverse spectral energy distribution (SED) shapes that deviate substantially from the well-characterized quasar templates. Motivated by the commonly seen UV-optical obscuration and the discovery of parsec-scale mid-IR polar du…
Statistics of Coronal Dimmings Associated with Coronal Mass Ejections. I. Characteristic Dimming Properties and Flare Association
Temmer, M.; Veronig, A. M.; Vanninathan, K. +2 more
Coronal dimmings, localized regions of reduced emission in the extreme-ultraviolet and soft X-rays (SXRs), are interpreted as density depletions due to mass loss during the coronal mass ejection (CME) expansion. They contain crucial information on the early evolution of CMEs low in the corona. For 62 dimming events, characteristic parameters are d…
HAZMAT. IV. Flares and Superflares on Young M Stars in the Far Ultraviolet
Loyd, R. O. Parke; Peacock, Sarah; Meadows, Victoria S. +4 more
M stars are powerful emitters of far-ultraviolet light. Over long timescales, a significant, possibly dominant, fraction of this emission is produced by stellar flares. Characterizing this emission is critical to understanding the atmospheres of the stars producing it and the atmospheric evolution of the orbiting planets subjected to it. Ultraviol…
The Intrinsic Characteristics of Galaxies on the SFR-M ∗ Plane at 1.2 < z < 4: I. The Correlation between Stellar Age, Central Density, and Position Relative to the Main Sequence
Ferguson, Henry C.; Giavalisco, Mauro; Kartaltepe, Jeyhan S. +12 more
We use the deep CANDELS observations in the GOODS North and South fields to revisit the correlations between stellar mass (M *), star formation rate (SFR) and morphology, and to introduce a fourth dimension, the mass-weighted stellar age, in galaxies at 1.2< z< 4. We do this by making new measures of M *, SFR, and stell…
HST Grism Confirmation of 16 Structures at 1.4 < z < 2.8 from the Clusters Around Radio-Loud AGN (CARLA) Survey
Noirot, Gaël; Gonzalez, Anthony H.; Stanford, S. A. +13 more
We report spectroscopic results from our 40-orbit Hubble Space Telescope slitless grism spectroscopy program observing the 20 densest Clusters Around Radio-Loud AGN (CARLA) candidate galaxy clusters at 1.4 < z < 2.8. These candidate rich structures, among the richest and most distant known, were identified on the basis of [3.6]-[4.5] color f…
The WFC3 Galactic Bulge Treasury Program: Relative Ages of Bulge Stars of High and Low Metallicity
Brown, Thomas M.; Gennaro, Mario; Anderson, Jay +6 more
The Hubble Space Telescope/WFC3 multiband photometry spanning from the UV to the near-IR of four fields in the Galactic bulge, together with that for six template globular and open clusters, are used to photometrically tag the metallicity [Fe/H] of stars in these fields after proper-motion rejecting most foreground disk contaminants. Color-magnitu…
Evidence for Merger-driven Growth in Luminous, High-z, Obscured AGNs in the CANDELS/COSMOS Field
Alexander, D. M.; Salvato, M.; Brusa, M. +27 more
While major mergers have long been proposed as a driver of both active galactic nucleus (AGN) activity and the {M}{BH}{--}{σ }{bulge} relation, studies of moderate to high-redshift Seyfert-luminosity AGN hosts have found little evidence for enhanced rates of interactions. However, both theory and observation suggest that whil…
Scientific Domain Knowledge Improves Exoplanet Transit Classification with Deep Learning
Jenkins, Jon M.; Ansdell, Megan; Osborn, Hugh P. +8 more
Space-based missions such as Kepler, and soon the Transiting Exoplanet Survey Satellite (TESS), provide large data sets that must be analyzed efficiently and systematically. Recent work by Shallue & Vanderburg successfully used state-of-the-art deep learning models to automatically classify Kepler transit signals as either exoplanets or false …