Search Publications
HO Puppis: Not a Be Star, but a Newly Confirmed IW And-type Star
Duev, Dmitry A.; Riddle, Reed; Mróz, Przemek +19 more
HO Puppis (HO Pup) was considered as a Be-star candidate based on its γ Cassiopeiae-type light curve, but lacked spectroscopic confirmation. Using distance measured from Gaia Data Release 2 and the spectral-energy-distribution fit on broadband photometry, the Be-star nature of HO Pup is ruled out. Furthermore, based on the 28,700 photometric data …
The Nature of HI-absorption-selected Galaxies at z ≈ 4
Prochaska, J. X.; Revalski, M.; Rafelski, M. +3 more
We report a Karl G. Jansky Very Large Array (JVLA) search for redshifted CO(1-0) or CO(2-1) emission, and a Hubble Space Telescope Wide Field Camera 3 (HST-WFC3) search for rest-frame near-ultraviolet (NUV) stellar emission, from seven HI-selected galaxies associated with high-metallicity ([M/H] ≥ -1.3) damped Lyα absorbers (DLAs) at z ≈ 4. The ga…
The First Extensive Exploration of UV-bright Stars in the Globular Cluster NGC 2808
Sahu, Snehalata; Subramaniam, Annapurni; Prabhu, Deepthi S.
In this study, we identified and characterized the hot and luminous UV-bright stars in the globular cluster NGC 2808. We combined data from the Ultra Violet Imaging Telescope (UVIT) on board the Indian space satellite AstroSat with the Hubble Space Telescope UV Globular Cluster Survey data for the central region (within $\sim 2\buildrel{\,\prime}\…
Optical Identification and Spectroscopy of Supernova Remnants in the Galaxy M51
Blair, William P.; Long, Knox S.; Winkler, P. Frank +2 more
Using a combination of ground-based and Hubble Space Telescope imaging, we have constructed a catalog of 179 supernova remnants (SNRs) and SNR candidates in the nearby spiral galaxy M51. Follow-up spectroscopy of 66 of the candidates confirms that 61 of these are SNRs and suggests that the vast majority of the unobserved objects are SNRs as well. …
Possible Periodic Dips in the Pulsating Ultraluminous X-Ray Source M51 ULX-7
Enoto, Teruaki; Ueda, Yoshihiro; Hu, Chin-Ping
We report the discovery of possible periodic X-ray dips in a pulsating ultraluminous X-ray source, M51 ULX-7, with archival Chandra observations. With ∼20 days of monitoring in the superorbital descending state, we discovered three dips with separations of ∼2 and ∼8 days via the Bayesian block technique. A phase-dispersion minimization and a ${\ch…
The H I Column Density Distribution of the Galactic Disk and Halo
Richter, Philipp; Heckman, Timothy; Savage, Blair D. +8 more
We present a census of neutral gas in the Milky Way disk and halo down to limiting column densities of N(H I) ~ 1014 cm-2 using measurements of H I Lyman series absorption from the Far Ultraviolet Spectroscopic Explorer. Our results are drawn from an analysis of 25 AGN sight lines spread evenly across the sky with Galactic la…
ALMA Observations of Lyα Blob 1: Multiple Major Mergers and Widely Distributed Interstellar Media
Ivison, R. J.; Smail, Ian; Hayes, Matthew +11 more
We present observations of a giant Lyα blob (LAB) in the SSA22 protocluster at z = 3.1, SSA22-LAB1, taken with the Atacama Large Millimeter/submillimeter Array. Dust continuum, along with [C II] 158 µm and CO(4-3) line emission have been detected in LAB1, showing complex morphology and kinematics across a ~100 kpc central region. Seven galax…
The VLA Frontier Fields Survey: Deep, High-resolution Radio Imaging of the MACS Lensing Clusters at 3 and 6 GHz
Smail, I.; Dickinson, M.; Jiménez-Andrade, E. F. +9 more
The Frontier Fields project is an observational campaign targeting six galaxy clusters, with the intention of using the magnification provided by gravitational lensing to study galaxies that are extremely faint or distant. We used the Karl G. Jansky Very Large Array (VLA) at 3 and 6 GHz to observe three Frontier Fields: MACS J0416.1-2403 (z = 0.39…
Testing for Dark Matter in the Outskirts of Globular Clusters
Grillmair, Carl J.; Carlberg, Raymond G.
The proper motions of stars in the outskirts of globular clusters are used to estimate cluster velocity dispersion profiles as far as possible within their tidal radii. We use individual color-magnitude diagrams to select high-probability cluster stars for 25 metal-poor globular clusters within 20 kpc of the Sun, 19 of which have substantial numbe…
An In Situ Study of Turbulence near Stellar Bow Shocks
Chatterjee, Shami; Dolch, Timothy; Cordes, James M. +1 more
Stellar bow shocks are observed in a variety of interstellar environments and shaped by the conditions of gas in the interstellar medium (ISM). In situ measurements of turbulent density fluctuations near stellar bow shocks are only achievable with a few observational probes, including Hα-emitting bow shocks and the Voyager Interstellar Mission (VI…