Search Publications
HST/COS Observations of Ionized Gas Accretion at the Disk-Halo Interface of M33
Peek, J. E. G.; Zheng, Y.; Putman, M. E. +1 more
We report the detection of accreting ionized gas at the disk-halo interface of the nearby galaxy M33. We analyze Hubble Space Telescope/Cosmic Origins Spectrograph absorption-line spectra of seven ultraviolet-bright stars evenly distributed across the disk of M33. We find Si IV absorption components consistently redshifted relative to the bulk M33…
The Outer Halo of the Milky Way as Probed by RR Lyr Variables from the Palomar Transient Facility
Kulkarni, Shrinivas R.; Laher, Russ R.; Prince, Thomas A. +5 more
RR Lyrae stars are ideal massless tracers that can be used to study the total mass and dark matter content of the outer halo of the Milky Way (MW). This is because they are easy to find in the light-curve databases of large stellar surveys and their distances can be determined with only knowledge of the light curve. We present here a sample of 112…
The Sleeping Monster: NuSTAR Observations of SGR 1806-20, 11 Years After the Giant Flare
Göğüş, Ersin; Kouveliotou, Chryssa; Younes, George +5 more
We report the analysis of five Nuclear Spectroscopic Telescope Array (NuSTAR) observations of SGR 1806-20 spread over a year from 2015 April to 2016 April, more than 11 years following its giant flare (GF) of 2004. The source spin frequency during the NuSTAR observations follows a linear trend with a frequency derivative \dot{ν }=(-1.25+/- 0.03)× …
Swift Observations of SMC X-3 during Its 2016-2017 Super-Eddington Outburst
Wang, Wei; Weng, Shan-Shan; Ge, Ming-Yu +4 more
The Be X-ray pulsar SMC X-3 underwent a giant outburst from 2016 August to 2017 March, which was monitored with the Swift satellite. During the outburst, its broadband flux increased dramatically, and the unabsorbed X-ray luminosity reached an extreme value of ∼ {10}39 erg s-1 around August 24. Using the Swift/XRT data, we me…
Astrometric Evidence for a Population of Dislodged AGNs
Chambers, Kenneth C.; Magnier, Eugene A.; Rest, Armin +5 more
We investigate a sample of 2293 ICRF2 extragalactic radio-loud sources with accurate positions determined by VLBI, mostly active galactic nuclei (AGNs) and quasars, which are cross-matched with optical sources in the first Gaia release (Gaia DR1). The distribution of offsets between the VLBI sources and their optical counterparts is strongly non-G…
HIFI Spectroscopy of H2O Submillimeter Lines in Nuclei of Actively Star-forming Galaxies
Menten, K. M.; van der Werf, P.; Stutzki, J. +10 more
We present a systematic survey of multiple velocity-resolved H2O spectra using Herschel/Heterodyne Instrument for the Far Infrared (HIFI) toward nine nearby actively star-forming galaxies. The ground-state and low-excitation lines (E up ≤ 130 K) show profiles with emission and absorption blended together, while absorption-fre…
Ultraviolet C II and Si III Transit Spectroscopy and Modeling of the Evaporating Atmosphere of GJ436b
Loyd, R. O. Parke; Redfield, Seth; France, Kevin +2 more
Hydrogen gas evaporating from the atmosphere of the hot-Neptune GJ436b absorbs over 50% of the stellar Lyα emission during transit. Given the planet’s atmospheric composition and energy-limited escape rate, this hydrogen outflow is expected to entrain heavier atoms such as C and O. We searched for C and Si in the escaping atmosphere of GJ436b usin…
The ISLAnds Project. III. Variable Stars in Six Andromeda Dwarf Spheroidal Galaxies
McQuinn, Kristen B. W.; Dolphin, Andrew E.; Skillman, Evan D. +15 more
We present a census of variable stars in six M31 dwarf spheroidal satellites observed with the Hubble Space Telescope. We detect 870 RR Lyrae (RRL) stars in the fields of And I (296), II (251), III (111), XV (117), XVI (8), and XXVIII (87). We also detect a total of 15 Anomalous Cepheids, three eclipsing binaries, and seven field RRL stars compati…
MC2: Multiwavelength and Dynamical Analysis of the Merging Galaxy Cluster ZwCl 0008.8+5215: An Older and Less Massive Bullet Cluster
Dawson, William A.; Jee, M. James; van Weeren, Reinout J. +2 more
We present and analyze a rich data set including Subaru/SuprimeCam, HST/Advanced Camera for Surveys and Wide Field Camera 3, Keck/DEIMOS, Chandra/ACIS-I, and JVLA/C and D array for the merging cluster of galaxies ZwCl 0008.8+5215. With a joint Subaru+HST weak gravitational lensing analysis, we identify two dominant subclusters and estimate the mas…
IRIS Burst Spectra Co-spatial to a Quiet-Sun Ellerman-like Brightening
Erdélyi, R.; Mathioudakis, M.; Oliver, R. +3 more
Ellerman bombs (EBs) have been widely studied over the past two decades; however, only recently have the counterparts of these events been observed in the quiet-Sun. The aim of this article is to further understand small-scale quiet-Sun Ellerman-like brightenings (QSEBs) through research into their spectral signatures, including investigating whet…