Search Publications
The Persistence of Memory, or How the X-Ray Spectrum of SNR 0509-67.5 Reveals the Brightness of Its Parent Type Ia Supernova
Hughes, John P.; Badenes, Carles; Bravo, Eduardo +1 more
We examine the dynamics and X-ray spectrum of the young Type Ia supernova remnant 0509-67.5 in the context of the recent results obtained from the optical spectroscopy of its light echo. Our goal is to estimate the kinetic energy of the supernova explosion using Chandra and XMM-Newton observations of the supernova remnant, thus placing the birth e…
Early Formation of Dust in the Ejecta of Type Ib SN 2006jc and Temperature and Mass of the Dust
Onaka, Takashi; Sakon, Itsuki; Tominaga, Nozomu +8 more
SN 2006jc is a peculiar supernova (SN), in which the formation of dust has been confirmed at an early epoch of ~50 days after the explosion. We investigate the possibility of such an early formation of dust grains in the expanding ejecta of SN 2006jc, applying the Type Ib SN model that is developed to reproduce the observed light curve. We find th…
Starburst Intensity Limit of Galaxies at z simeq 5-6
Hathi, N. P.; Malhotra, S.; Rhoads, J. E.
The peak star formation intensity in starburst galaxies does not vary significantly from the local universe to redshift z ~ 6. We arrive at this conclusion through new surface brightness measurements of 47 starburst galaxies at z simeq 5-6, doubling the redshift range for such observations. These galaxies are spectroscopically confirmed in the Hub…
T Tauri Jet Physics Resolved Near the Launching Region with the Hubble Space Telescope
Bacciotti, Francesca; Coffey, Deirdre; Podio, Linda
We present an analysis of the gas physics at the base of jets from five T Tauri stars based on high angular resolution optical spectra, using the Hubble Space Telescope Imaging Spectrograph (HST STIS). The spectra refer to a region within 100 AU of the star, i.e., where the collimation of the jet has just taken place. We form position-velocity (PV…
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…