Search Publications
Initial Measurements of Black Hole Spin in GX 339-4 from Suzaku Spectroscopy
Fabian, A. C.; Miller, J. M.; Reynolds, C. S. +6 more
We report on a deep Suzaku observation of the stellar-mass black hole GX 339-4 in outburst. A clear, strong, relativistically shaped iron emission line from the inner accretion disk is observed. The broadband disk reflection spectrum revealed is one of the most sensitive yet obtained from an accreting black hole. We fit the Suzaku spectra with a p…
The Origin of the Intrinsic Scatter in the Relation Between Black Hole Mass and Bulge Luminosity for Nearby Active Galaxies
Ho, Luis C.; Barth, Aaron J.; Im, Myungshin +4 more
We investigate the origin of the intrinsic scatter in the correlation between black hole mass (MBH) and bulge luminosity (Lbul) in a sample of 45 massive, local (zlesssim 0.35) type 1 active galactic nuclei (AGNs). We derive MBH from published optical spectra assuming a spherical broad-line region, and Lbul
Determining Atmospheric Conditions at the Terminator of the Hot Jupiter HD 209458b
Sing, David K.; Ehrenreich, D.; Lecavelier des Etangs, A. +3 more
We present a theoretical model fit to the HST STIS optical transit transmission spectrum of HD 209458b. In our fit, we use the sodium absorption line profile along with the Rayleigh scattering by H2 to help determine the average temperature-pressure profile at the planetary terminator and infer the abundances of atomic and molecular spe…
XMM-Newton Observations of the Narrow-Line Seyfert 1 Galaxy Mrk 335 in a Historical Low X-Ray Flux State
Fabian, Andrew C.; Gallo, Luigi C.; Miniutti, Giovanni +5 more
We report the discovery of strong soft X-ray emission lines and a hard continuum above 2 keV in the narrow-line Seyfert 1 galaxy Mrk 335 during an extremely low X-ray flux state. Mrk 335 was observed for 22 ks by XMM-Newton in 2007 July as a Target of Opportunity to examine it in its X-ray low flux state, which was discovered with Swift. Long-term…
The Detection of a Light Echo from the Type Ia Supernova 2006X in M100
Filippenko, Alexei V.; Foley, Ryan J.; Smith, Nathan +3 more
We report the discovery of a light echo (LE) from the Type Ia supernova (SN) 2006X in the nearby galaxy M100. The presence of the LE is supported by analysis of both the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) images and the Keck optical spectrum that we obtained at ~300 days after maximum brightness. In the image procedure,…
Blue Straggler Stars in the Unusual Globular Cluster NGC 6388
Dalessandro, E.; Valenti, E.; Piotto, G. +4 more
We have used multiband high-resolution HST WFPC2 and ACS observations combined with wide-field ground-based observations to study the blue straggler star (BSS) population in the Galactic globular cluster NGC 6388. As in several other clusters we have studied, the BSS distribution is found to be bimodal: highly peaked in the cluster center, rapidly…
CHARA Array Measurements of the Angular Diameters of Exoplanet Host Stars
Goldfinger, P. J.; McAlister, Harold A.; ten Brummelaar, Theo A. +5 more
We have measured the angular diameters for a sample of 24 exoplanet host stars using Georgia State University's CHARA Array interferometer. We use these improved angular diameters together with Hipparcos parallax measurements to derive linear radii and to estimate the stars' evolutionary states.
The Energy Flux of Internal Gravity Waves in the Lower Solar Atmosphere
McIntosh, Scott W.; Straus, Thomas; Fleck, Bernhard +5 more
Stably stratified fluids, such as stellar and planetary atmospheres, can support and propagate gravity waves. On Earth these waves, which can transport energy and momentum over large distances and can trigger convection, contribute to the formation of our weather and global climate. Gravity waves also play a pivotal role in planetary sciences and …
Radially Inflowing Molecular Gas in NGC 1275 Deposited by an X-Ray Cooling Flow in the Perseus Cluster
Lim, Jeremy; Dinh-V-Trung; Ao, YiPing
We have imaged in CO(2-1) the molecular gas in NGC 1275 (Perseus A), the cD galaxy at the center of the Perseus Cluster, at a spatial resolution of ~1 kpc over a central region of radius ~10 kpc. Per A is known to contain ~1.3 × 1010 M⊙ of molecular gas, which has been proposed to be captured from mergers with or ram pressure…
X-Ray Spectroscopy of the 2006 Outburst of RS Ophiuchi
Orio, Marina; Still, Martin; Nelson, Thomas +3 more
We present X-ray grating spectra of the recurrent nova RS Ophiuchi during its 2006 outburst, obtained with XMM-Newton and Chandra. For the first month after optical maximum, the X-ray spectrum was hard and dominated by emission lines of H-like and He-like ions. The X-ray luminosity was 2.4 × 1036 ergs s-1 in the 0.33-10 keV r…