Search Publications
A Long, Hard Look at the Low/Hard State in Accreting Black Holes
Wijnands, R.; Fabian, A. C.; Miller, J. M. +5 more
We present the first results of coordinated multiwavelength observations of the Galactic black hole GX 339-4 in a canonical low/hard state, obtained during its 2004 outburst. XMM-Newton observed the source for two revolutions, or approximately 280 ks; RXTE monitored the source throughout this long stare. The resulting data offer the best view yet …
Pixie Dust: The Silicate Features in the Diffuse Interstellar Medium
Tielens, A. G. G. M.; Chiar, J. E.
We have analyzed the 9.7 and ``18'' µm interstellar silicate absorption features along the line of sight toward four heavily extincted galactic WC-type Wolf-Rayet (WR) stars. We construct two interstellar extinction curves from 1.25 to 25 µm using near-IR extinction measurements from the literature, along with the silicate profiles of …
The Sloan Lens ACS Survey. II. Stellar Populations and Internal Structure of Early-Type Lens Galaxies
Treu, Tommaso; Bolton, Adam S.; Burles, Scott +2 more
We use HST images to derive effective radii and effective surface brightnesses of 15 early-type (E+S0) lens galaxies identified by the SLACS Survey. Our measurements are combined with stellar velocity dispersions from the SDSS database to investigate for the first time the distribution of lens galaxies in the fundamental plane (FP) space. Accounti…
Solar Differential Rotation Influenced by Latitudinal Entropy Variations in the Tachocline
Toomre, Juri; Brun, Allan Sacha; Miesch, Mark S.
Three-dimensional simulations of solar convection in spherical shells are used to evaluate the differential rotation that results as thermal boundary conditions are varied. In some simulations a latitudinal entropy variation is imposed at the lower boundary in order to take into account the coupling between the convective envelope and the radiativ…
Discovery of Luminous Pulsed Hard X-Ray Emission from Anomalous X-Ray Pulsars 1RXS J1708-4009, 4U 0142+61, and 1E 2259+586 by INTEGRAL and RXTE
Kuiper, L.; Hermsen, W.; den Hartog, P. R. +1 more
We investigated the time-averaged high-energy spectral characteristics of the persistent anomalous X-ray pulsars (AXPs) 1RXS J1708-4009, 4U 0142+61, 1E 2259+586, and 1E 1048.1-5937, using RXTE PCA (2-60 keV), RXTE HEXTE (15-250 keV), and INTEGRAL IBIS ISGRI (20-300 keV) data. We discovered hard spectral tails for energies above 10 keV in the total…
A Spectroscopic Survey of Redshift 1.4<~z<~3.0 Galaxies in the GOODS-North Field: Survey Description, Catalogs, and Properties
Pettini, Max; Erb, Dawn K.; Shapley, Alice E. +2 more
We present the results of a spectroscopic survey with LRIS-B on Keck of more than 280 star-forming galaxies and AGNs at redshifts 1.4<~z<~3.0 in the GOODS-N field. Candidates are selected by their UnGR colors using the ``BM/BX'' criteria to target redshift 1.4<~z<~2.5 galaxies and the LBG criteria to target redshift z~3 gala…
Constraints on the Physics of Type Ia Supernovae from the X-Ray Spectrum of the Tycho Supernova Remnant
Hughes, John P.; Hwang, Una; Badenes, Carles +2 more
In this paper we use high-quality X-ray observations from XMM-Newton and Chandra to gain new insights into the explosion that originated Tycho's supernova 433 yr ago. We perform a detailed comparison between the ejecta emission from the spatially integrated X-ray spectrum of the supernova remnant and current models for Type Ia supernova explosions…
A Model for Spectral and Compositional Variability at High Energies in Large, Gradual Solar Particle Events
Lee, Martin A.; Tylka, Allan J.
Shocks driven by fast coronal mass ejections (CMEs) are generally believed to be the dominant accelerators in large, gradual solar energetic particle (SEP) events. A key challenge for this notion has been the highly variable spectral and compositional characteristics of these events above a few tens of MeV per nucleon. We have recently proposed th…
Nearby Debris Disk Systems with High Fractional Luminosity Reconsidered
Apai, D.; Derekas, A.; Ábrahám, P. +5 more
By searching the IRAS and ISO databases, we compiled a list of 60 debris disks that exhibit the highest fractional luminosity values (fd>10-4) in the vicinity of the Sun (d<120 pc). Eleven out of these 60 systems are new discoveries. Special care was taken to exclude bogus disks from the sample. We computed the fraction…
Fe II Emission in 14 Low-Redshift Quasars. I. Observations
Oyabu, Shinki; Tanabé, Toshihiko; Matsuoka, Yoshiki +3 more
We present the spectra of 14 quasars with a wide coverage of rest wavelengths from 1000 to 7300 Å. The redshift ranges from z=0.061 to 0.555 and the luminosity from MB=-22.69 to -26.32. These spectra of high quality result from combining Hubble Space Telescope spectra with those taken from ground-based telescopes. We describe the proced…