Search Publications
Ultraviolet Imagery of NGC 6752: A Test of Extreme Horizontal Branch Models
O'Connell, Robert W.; Sweigart, Allen V.; Bohlin, Ralph C. +5 more
We present a 1620 A image of the nearby globular cluster NGC 6752 obtained with the Ultraviolet Imaging Telescope (UIT) during the Astro-2 mission of the Space Shuttle Endeavour in 1995 March. An ultraviolet-visible color-magnitude diagram (CMD) is derived for 216 stars matched with the visible photometry of Buonanno et al. This CMD provides a nea…
The Mid-Infrared Evolution of Nova V1974 Cygni
Hayward, T. L.; Saizar, P.; Gehrz, R. D. +6 more
We observed nova V1974 Cygni (1992) at mid-infrared wavelengths λ = 7.5-13 µm nine times between 1992 April (54 days after the outburst) and 1994 July (day 882). Low- and medium-resolution spectra recorded the evolution of hydrogen recombination lines, free-free continuum emission, and the [Ne II] 12.8 µm, [Ne VI] 7.6 µm, and [Mg…
The Gaseous Extent of Galaxies and the Origin of LY alpha Systems. II. Identification of a Group or Cluster of LY alpha Absorbing Galaxies at Z approximately equal to 0.26
Lanzetta, Kenneth M.; Webb, John K.; Barcons, Xavier
We report the identification of a group or cluster of galaxies at redshift z ~ 0.26 toward the quasi-stellar object (QSO) 1545+2101 that produces a complex of corresponding Ly alpha absorption systems. This observation demonstrates that at least some groups or clusters of galaxies produce Ly alpha absorption systems and that at least some Ly alpha…
The Wind Outflow of zeta Aurigae: A Model Revision Using Hubble Space Telescope Spectra
Harper, Graham M.; Bennett, Philip D.; Brown, Alexander +4 more
Using high-resolution spectra taken with the Goddard High-Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope (HST) and with the International Ultraviolet Explorer (lUE) satellite, we reconsider the wind model of ζ Aurigae (K4 Ib + B5 V). The high quality of the HST data permits a critical test of the simplifying assumptions previousl…
A Candidate Gravitational Lens in the Hubble Deep Field
Hogg, David W.; Fassnacht, C. D.; Blandford, Roger +2 more
The discovery of HDF J123652+621227, a candidate gravitational lens in the Hubble Deep Field, is reported. This lens may be multiply imaging several optical sources at different redshifts. If follow-up spectroscopy of the lens and the brightest image confirms this hypothesis, observations of this system alone can be used to obtain an estimate of t…
Spectroscopy of Bright Quasars with the Hubble Space Telescope and Lyman-Alpha Absorption Lines in the Redshift Range 0.5 < Z < 1.7
Malkan, M. A.; Impey, C. D.; Petry, C. E. +1 more
We report ultraviolet spectroscopy of three bright quasars obtained with the Faint Object Spectrograph of the Hubble Space Telescope. The good quality spectra covering the range 1800-3300 A result from spectropolarimetry acquired for these targets, the interpretation of which has been published elsewhere. Objective algorithms were used to select a…
Hubble Space Telescope Observations of the Seyfert Galaxy NGC 3783: Discovery of Variable C IV Absorption
Hutchings, John B.; Reichert, Gail A.; Mushotzky, Richard F. +5 more
We have discovered variable absorption lines in HST spectra of the Seyfert 1 galaxy NGC 3783. C IV λλ1548.2, 1550.8 absorption is present in an FOS spectrum on 1992 July 27 and a GHRS spectrum on 1994 January 16 at a radial velocity of -450 km s^-1^ relative to the emission-line peak, but there is no evidence for absorption in a GHRS spectrum on 1…
Hubble Space Telescope/FOS Spectroscopy of VW Hydri in Superoutburst
Szkody, P.; Sion, E. M.; Huang, M. +2 more
We present an analysis of two HST/FOS UV spectra of the SU UMa type dwarf nova, VW Hyi, obtained on 1993 October 24, ∼5 days after the optical rise of a superoutburst The absorption features in the first spectrum appear to consist of two components: a broad-winged component (with velocity width of 3000 km s-1) and a sharp core narrow co…
The Masses and Radii of the Eclipsing Binary zeta Aurigae
Harper, Graham M.; Bennett, Philip D.; Brown, Alexander +1 more
We present a full determination of the fundamental stellar and orbital parameters of the eclipsing binary ζ Aurigae (K4 Ib + BS V) using recent observations with the Hubble Space Telescope Goddard High Resolution Spectrograph (GHRS) and the Mark III long-baseline optical interferometer. The information obtained from spectroscopic and interferometr…
A Long EUVE Observation of the Seyfert Galaxy RX J0437.4-4711
Halpern, Jules P.; Marshall, Herman L.
We monitored the soft X-ray-selected Seyfert galaxy RX J0437.4 - 4711 with the EUVE satellite continuously for 20 days in 1994 October- November. The Seyfert was detected in the 70-110 A range, both in the short-wavelength spectrometer and in the Deep Survey imager. Its light curve shows large-amplitude variability by a factor of 4 over the 20 day…