Search Publications
Abundances and Physical Conditions in the Warm Neutral Medium toward µ Columbae
Savage, Blair D.; Howk, J. Christopher; Fabian, Dirk
We present ultraviolet interstellar absorption-line measurements for the sightline toward the O9.5 V star µ Columbae (l=237.3d, b=-27.1d d~400 pc, z~180 pc; <nHI>~0.06 cm-3) obtained with the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope. These archival data represent the most com…
Triple Bars and Complex Central Structures in Disk Galaxies
Erwin, Peter; Sparke, Linda S.
We present an analysis of ground-based and Hubble Space Telescope images of three early-type barred galaxies. The first, NGC 2681, may be the clearest example yet of a galaxy with three concentric bars. The two other galaxies were previously suggested to be triple barred. Our analysis shows that while NGC 3945 is probably double barred, NGC 4371 h…
Molecular Gas in 3C 293: The First Detection of CO Emission and Absorption in a Fanaroff-Riley Type II Radio Galaxy
Sanders, D. B.; Surace, J. A.; Evans, A. S. +1 more
The first detection of CO emission in a Fanaroff and Riley type II (i.e., edge-brightened radio lobe morphology) radio galaxy is presented. Multiwavelength (0.36-2.17 µm) imaging of 3C 293 shows it to be a disk galaxy with an optical jet or tidal tail extending toward what appears to be a companion galaxy 28 kpc away via a low surface bright…
Optical-Radio Alignment in Compact Steep-Spectrum Radio Sources
O'Dea, C. P.; Baum, S. A.; de Vries, W. H. +1 more
We discuss Hubble Space Telescope (HST) WFPC2 observations through the broad red filter F702Wof 30 3CR sources from the Compact Steep Spectrum (CSS) radio source sample, and present 11 new HST/WFPC2 images through linear ramp filters (LRF), isolating either rest-frame [O II] 3727 Å or[O III] 5007 Å radiation. In nearly all the CSS galaxies, we fin…
Parallaxes versus p-Modes: Comparing HIPPARCOS and Asteroseismic Results for Pulsating AP Stars
Kurtz, D. W.; Matthews, Jaymie M.; Martinez, Peter
The p-mode eigenfrequency spacings of 12 rapidly oscillating Ap (roAp) stars provide estimates of their radii. By combining these with independent estimates of their effective temperatures via Hβ photometry, Martinez predicted luminosities for all but one of this sample. Hipparcos parallaxes, and hence luminosities, are now available for the entir…
GHRS Observations of the White Dwarf in U Geminorum
Gilliland, Ronald L.; Long, Knox S.
We have observed the dwarf nova U Geminorum while it was in quiescence in the wavelength range 1162-1448 Å using the GHRS on Hubble Space Telescope. The time-resolved (λ/δλ=2000) spectra are dominated by the white dwarf in the system. By analyzing the Doppler shifts of the photospheric metal absorption lines that punctuate the spectrum, we have ac…
Molecular Gas in the Powerful Radio Nucleus of the Ultraluminous Infrared Galaxy PKS 1345+12
Sanders, D. B.; Scoville, N. Z.; Evans, A. S. +2 more
Millimeter CO (1 --> 0) interferometry and high-resolution, Hubble Space Telescope 1.1, 1.6, and 2.2 µm imaging of the radio compact galaxy PKS 1345+12 are presented. With an infrared luminosity of ~2×1012 Lsolar, PKS 1345+12 is a prime candidate for studying the link between the ultraluminous infrared galaxy phenome…
Reactivation and Precise Interplanetary Network Localization of the Soft Gamma Repeater SGR 1900+14
Cline, T.; Hurley, K.; Kouveliotou, C. +5 more
In 1998 May, the soft gamma repeater SGR 1900+14 emerged from several years of quiescence and emitted a series of intense bursts, one with a time history unlike any previously observed from this source. Triangulation using Ulysses, BATSE, and KONUS data gives a 1.6 arcmin2 error box near the Galactic supernova remnant G42.8+0.6. This er…
Ultraviolet Interstellar Linear Polarization. V. Analysis of the Final Data Set
Martin, P. G.; Clayton, Geoffrey C.; Wolff, Michael J.
Using recent measurements of ultraviolet interstellar polarization, we have examined its relationship to ultraviolet extinction and to polarization and extinction measurements in the visible and infrared. The relationship between the relative amount of ultraviolet polarization and the parameter λmax, determined using only visible data, …
Determining the Physical Properties of the B Stars. I. Methodology and First Results
Fitzpatrick, Edward L.; Massa, Derck
We describe a new approach to fitting the UV-to-optical spectra of B stars to model atmospheres and present initial results. Using a sample of lightly reddened stars, we demonstrate that the Kurucz model atmospheres can produce excellent fits to either combined low-dispersion IUE and optical photometry or HST FOS spectrophotometry, as long as the …