Search Publications
Mid-IR Observations and a Revised Time Delay for the Gravitational Lens System Quasar HE 1104-1805
Kochanek, Christopher S.; Falco, Emilio E.; Poindexter, Shawn +1 more
The mid-IR flux ratios FA/FB=2.84+/-0.06 of the two images of the gravitationally lensed quasar HE 1104-1805 show no wavelength dependence to within 3% across 3.6-8.0 µm, show no time dependence over 6 months, and agree with the broad emission-line flux ratios. This indicates that the mid-IR emission likely comes from s…
A Normal Stellar Disk in the Galaxy Malin 1
Barth, Aaron J.
Since its discovery, Malin 1 has been considered the prototype and most extreme example of the class of giant low surface brightness disk galaxies. Examination of an archival Hubble Space Telescope I-band image reveals that Malin 1 contains a normal stellar disk that was not previously recognized, having a central I-band surface brightness of &mic…
A Systematic Search for High Surface Brightness Giant Arcs in a Sloan Digital Sky Survey Cluster Sample
Allam, S.; Annis, J.; Diehl, H. T. +8 more
We present the results of a search for gravitationally lensed giant arcs conducted on a sample of 825 SDSS galaxy clusters. Both a visual inspection of the images and an automated search were performed, and no arcs were found. This result is used to set an upper limit on the arc probability per cluster. We present selection functions for our surve…
Hadriaca Patera: Insights into its volcanic history from Mars Express High Resolution Stereo Camera
Greeley, Ronald; Williams, David A.; Neukum, Gerhard +6 more
High Resolution Stereo Camera (HRSC) images of Hadriaca Patera, Mars, in combination with Mars Orbiter Camera (MOC), Mars Orbiter Laser Altimeter (MOLA), and Thermal Infrared Imaging System (THEMIS) data sets, reveal morphologic details about this volcano and enable determination of a chronology of the major geologic events through new cratering a…
A Radio Nebula Surrounding the Ultraluminous X-Ray Source in NGC 5408
Kaaret, Philip; Corbel, Stéphane; Lang, Cornelia C. +1 more
New radio observations of the counterpart of the ultraluminous X-ray source in NGC 5408 show for the first time that the radio emission is resolved with an angular size of 1.5"-2.0". This corresponds to a physical size of 35-46 pc, and rules out interpretation of the radio emission as beamed emission from a relativistic jet. In addition, the radio…
Formation of Titan in Saturn's subnebula: constraints from Huygens probe measurements
Alibert, Y.; Mousis, O.
We present an evolutionary turbulent model of the Saturn's subnebula consistent with recent core accretion formation models of Saturn. Our calculations are similar to those conducted in the case of the Jovian subnebula, and take into account the vertical structure of the disk, as well as the evolution of its surface density, as given by an α-disk …
Smooth and Starburst Tidal Tails in the GEMS and GOODS Fields
Elmegreen, Bruce G.; Elmegreen, Debra Meloy; Ferguson, Thomas +1 more
GEMS and GOODS fields were examined to z~1.4 for galaxy interactions and mergers. The basic morphologies are familiar: antennae with long tidal tails, tidal dwarfs, and merged cores; M51-type galaxies with disk spirals and tidal arm companions; early-type galaxies with diffuse plumes; equal-mass grazing collisions; and thick J-shaped tails beaded …
Discovery of Probable Relativistic Fe Emission and Absorption in the Cloverleaf Quasar H 1413+117
Agol, E.; Dai, X.; Chartas, G. +2 more
We present results from Chandra and XMM-Newton observations of the low-ionization broad absorption line (LoBAL) quasar H 1413+117. Our spatial and spectral analysis of a recent deep Chandra observation confirms a microlensing event in a previous Chandra observation performed about five years earlier. We present constraints on the structure of the …
On the Metallicity Dependence of the 24 µm Luminosity as a Star Formation Tracer
Battaner, E.; Relaño, M.; Vílchez, J. M. +2 more
We investigate the use of the rest-frame 24 µm luminosity as an indicator of the star formation rate (SFR) in galaxies with different metallicities by comparing it to the (extinction-corrected) Hα luminosity. We carry out this analysis in two steps: First, we compare the emission from H II regions in different galaxies with metallicities bet…
X-ray emission from the stellar population in M 32
Revnivtsev, M.; Sazonov, S.; Churazov, E. +2 more
Using Chandra observations, we study the X-ray emission of the stellar population in the compact dwarf elliptical galaxy M 32. The proximity of M 32 allows one to resolve all bright point sources with luminosities higher than 8×1033~erg~s-1 in the 0.5-7 keV band. The remaining (unresolved) emission closely follows the galaxy'…