Search Publications
X-Ray Emission from PSR J1809-1917 and Its Pulsar Wind Nebula, Possibly Associated with the TeV Gamma-Ray Source HESS J1809-193
Pavlov, G. G.; Kargaltsev, O.
We detected the 50 kyr old pulsar J1809-1917, and resolved its pulsar wind nebula (PWN) with the Chandra X-Ray Observatory. The pulsar spectrum fits a power-law+blackbody (PL+BB) model, with a photon index Γpsr=1.2+/-0.6 and T~2 MK for nH=0.7×1022 cm-2. At a distance of 3.5 kpc, the luminosities of the P…
Three-dimensional Numerical Simulations of the Acoustic Wave Field in the Upper Convection Zone of the Sun
Kosovichev, A. G.; Parchevsky, K. V.
Results of numerical three-dimensional (3D) simulations of propagation of acoustic waves inside the Sun are presented. A linear 3D code which utilizes the realistic OPAL equation of state was developed. A modified convectively stable standard solar model with a smoothly joined chromosphere was used as a background model. A high-order dispersion re…
On the Remote Galactic Globular Cluster NGC 2419
Marconi, Marcella; Dall'Ora, Massimo; Ripepi, Vincenzo +8 more
We present a new, deep (V~26) study of the Galactic globular cluster NGC 2419 based on B, V, I time-series CCD photometry over about 10 years and extending beyond the cluster published tidal radius. We have identified 101 variable stars, of which 60 are new discoveries, doubling the known RR Lyrae stars and including 12 SX Phoenicis stars. The ave…
A Spectroscopic Study of Mass Outflows in the Interacting Binary RY Scuti
Gies, Douglas R.; Smith, Nathan; Gehrz, Robert D. +5 more
The massive interacting binary RY Scuti is an important representative of an active mass-transferring system that is changing before our eyes and which may be an example of the formation of a Wolf-Rayet star through tidal stripping. Utilizing new and previously published spectra, we present examples of how a number of illustrative absorption and e…
Early Ultraviolet, Optical, and X-Ray Observations of the Type IIP SN 2005cs in M51 with Swift
Modjaz, Maryam; Kirshner, Robert P.; Dewangan, Gulab C. +14 more
We report early photospheric-phase observations of the Type IIP supernova (SN) 2005cs obtained by the Swift ultraviolet-optical and X-ray telescopes. Observations started within 2 days of discovery and continued on a regular basis for 3 weeks. During this time the V-band magnitude remained essentially constant, while the UV was initially bright, b…
The Microjansky Radio Galaxy Population
Wang, W. -H.; Barger, A. J.; Cowie, L. L.
We use highly spectroscopically complete observations of the radio sources from the VLA 1.4 GHz survey of the Hubble Deep Field-North region to study the faint radio galaxy population and its evolution. The fraction that can be optically spectroscopically identified is fairly independent of radio flux, with about 60%-80% identified at all fluxes. …
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 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…
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…
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 …