Search Publications
Source Matching in the SDSS and Rass: which Galaxies are Really X-Ray Sources?
Hoyle, Fiona; Parejko, John K.; Constantin, Anca +1 more
The current view of galaxy formation holds that all massive galaxies harbor a massive black hole at their center, but that these black holes are not always in an actively accreting phase. X-ray emission is often used to identify accreting sources, but for galaxies that are not harboring quasars (low-luminosity active galaxies), the X-ray flux may …
Hubble Space Telescope/Advanced Camera for Surveys Narrowband Imaging of the Kepler Supernova Remnant
Blair, William P.; Rudnick, Lawrence; Harrus, Ilana M. +4 more
We present narrowband images of the Kepler supernova remnant obtained with the Advanced Camera for Surveys aboard the Hubble Space Telescope. The images, with an angular resolution of 0.05'', reveal the structure of the emitting gas in unprecedented detail. Radiative and nonradiative shocks are found in close proximity, unresolvable in ground-base…
The Absolute Flux Distribution of LDS749B
Koester, D.; Bohlin, R. C.
Observations from the Space Telescope Imaging Spectrograph (STIS) define the flux of the DBQ4 star LDS749B from 0.12 to 1.0 µm with an uncertainty of ~1% relative to the three pure hydrogen white dwarf primary Hubble Space Telescope standards. With T eff = 13,575 K, log g = 8.05, and a trace of carbon at 1 × 10-6 of sol…
Variable X-Ray Absorption Toward the Gravitationally-Lensed Blazar PKS 1830-211
Garmire, Gordon P.; Mathur, Smita; Dai, Xinyu +2 more
We present X-ray spectral analysis of five Chandra and XMM-Newton observations of the gravitationally-lensed blazar PKS 1830-211 from 2000 to 2004. We show that the X-ray absorption toward PKS 1830-211 is a variable, and the variable absorption is most likely to be intrinsic with amplitudes of ~2 × 1022 30 × 1022 cm-2
A Model for the Chromosphere/Wind of 31 Cygni and Its Implications for Single Stars
Eaton, Joel A.
I develop a detailed empirical model for the chromosphere and wind of 31 Cyg based on a previously published analysis of International Ultraviolet Explorer spectra from the 1993 eclipse and on the thermodynamics of how the wind must be driven. I then use this model to interpret observations of single supergiant stars and to assess the evidence tha…
Normal Globular Cluster Systems in Massive Low Surface Brightness Galaxies
Jordán, Andrés; Kissler-Patig, Markus; Goudfrooij, Paul +2 more
We present the results of a study of the globular cluster systems of six massive spiral galaxies, originally cataloged as low surface brightness (LSB) but here shown to span a wide range of surface brightness values, including two intermediate to LSB galaxies. We used the Advanced Camera for Surveys on-board Hubble Space Telescope to obtain photom…
The XMM-Newton X-Ray Emission of the Supernova Remnant N 120 in the Large Magellanic Cloud
Rosado, Margarita; Reyes-Iturbide, Jorge; Velázquez, Pablo F.
We present new XMM-Newton observations of the supernova remnant (SNR) N 120 in the Large Magellanic Cloud, and numerical simulations on the evolution of this SNR which we compare with the X-ray observations. The SNR N 120, together with several H II regions, forms a large nebular complex (also called N 120) whose shape resembles a semicircular rin…
Detection of X-Ray Elongated Emission from AN Ultraluminous X-Ray Source in the Interacting Pair of Galaxies NGC 5953/5954
Ghosh, Kajal K.; Rosado, Margarita; Fuentes-Carrera, Isaura
We present radio through X-ray observations of a bright (>1040 erg s-1 in the 0.5-8.0 keV band) ultraluminous X-ray source (ULX), CXOU J153434.9+151149, in the starburst, interacting pair of galaxies NGC 5953/5954. A Chandra image of this ULX shows that it is elongated. From HST/WFPC2/F606W data we have detected a counterp…
Spatial Extension in the Ultraviolet Spectrum of VV Cephei
Bennett, Philip D.; Gull, Theodore R.; Hagen Bauer, Wendy
Two-dimensional processing of Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) echelle spectra of the eclipsing M2 Iab + B binary system, VV Cep, has revealed extended emission in all 21 epochs observed, ranging from midtotality through the first quadrature. In the ultraviolet accessible to STIS (1150- 3150 Å), essentially al…
The Ringed Spiral Galaxy NGC4622. II. An Independent Determination that the Two Outer Arms Lead
Byrd, Gene G.; Freeman, Tarsh; Buta, Ronald J. +1 more
The spiral galaxy NGC4622 was recognized by Byrd et al. (1989, Celest. Mech., 45, 31) to have a single inner arm winding outward counterclockwise (CCW) and an outer pair of arms winding outward clockwise (CW). Using HST and ground-based observations, Buta et al. (2003, AJ, 125, 634) used a dust silhouette method to determine that the disk of NGC46…