Search Publications
The Snapshot Survey: A Search for Gravitationally Lensed Quasars with the Hubble Space Telescope
Maoz, D.; Lahav, O.; Schneider, D. P. +4 more
In a systematic attempt to find new examples of multiply imaged quasars that are the result of gravitational lensing, 89 short exposures, through two filters, of high-luminosity quasars from a well-defined sample have been obtained with the Hubble Space Telecope's Planetary Camera. Useful high-resolution images of approximately 30 quasars have res…
Hubble Space Telescope Imaging of Distant Galaxies: 4C 41.17 at Z = 3.8
Chambers, K. C.; Macchetto, F.; Miley, G. K. +1 more
The Hubble Space telescope has been used to image the continuum emission from 4C 41.17 at z = 3.8, the most distant galaxy known. The galaxy was detected with good signal-to-noise ratio and was spatially resolved at the 0.1" (440 pc) HST resolution. The measured integrated flux density is in good agreement with the ground-based value (R~22). About…
The Optical Variability of PKS 2155-304
Miller, H. R.; Carini, Michael T.
The BL Lacertae object, PKS 2155 - 304, has been photometrically monitored for the past decade (1979-1990). Optical variations have been observed on time scales ranging from several minutes to several years. The variations detected with time scales on the order of minutes are among the fastest optical variations detected for a BL Lacertae object. …
Properties of the Massive X-Ray Binary 4U 1700-37 = HD 153919
Corcoran, M. F.; Heap, S. R.
The system parameters for the massive X-ray binary 4U 1700 - 37 are reexamined in the light of modern spectroscopic theory and new UV and X-ray data. The system is composed of HD 153919, an O6f star having a stronger wind, and an accreting neutron star. Revised parameters for the Of component are derived which are in accord with the parameters of …
CNO Abundances and Temperature Fluctuations in the Orion Nebula
Dufour, Reginald J.; Hester, J. J.; Walter, Donald K.
The largest UV-optical data base to date of the Orion Nebula has been assembled, and the CNO abundances their distribution at a statistically significant number of positions to the north and west of the Trapezium and out to a distance of 5 arcmin has been examined. The forbidden O III temperature increases with distance from Theta1 Ori C while the…
Observations of R Coronae Borealis Stars in Decline: Empirical Arguments for Dust Formation near the Stellar Surface
Stanford, S. A.; Clayton, Geoffrey C.; Drilling, John S. +1 more
We present new IUE observations which monitor the spectroscopic evolution of RY Sgr through a deep decline. These data, along with other IUE, visible, and infrared observations of declines in RY Sgr, R CrB, and V854 Cen, are considered in an attempt to understand the dust formation process and the source of the narrow- and broad-line emission seen…
Iron Abundance in the Hot DA White Dwarfs Feige 24 and G191 B2B
Thorstensen, John R.; Bowyer, Stuart; Vennes, Stephane +2 more
Attention is given to model calculations of the far- and extreme-UV line spectra of highly ionized Fe species (Fe IV, Fe V, and Fe VI) for hot high-gravity H-rich stars. A spectral analysis of 31 hr of exposure of the DA white dwarf Feige 24 with IUE in the echelle mode reveals the presence of Fe with an abundance relative to H by number of (5-10)…
The Interstellar Deuterium-to-Hydrogen Ratio: A Reevaluation of Lyman Absorption-Line Measurements
McCullough, Peter R.
The D/H ratio in the local interstellar medium is evaluated based upon previously published measurements of Lyman absorption lines together with the hypothesis that the D/H ratio is constant. A unique value for the D/H ratio of 1.5 (+/- 0.2) x 10 exp -5 by number is shown to be consistent with all published determinations made with the Copernicus …
Tomographic Separation of Composite Spectra. I. The Components of Plaskett's Star
Wiggs, Michael S.; Gies, Douglas R.; Bagnuolo, William G., Jr.
The UV photospheric lines of Plaskett's Star (HD 47129), a 14.4 day period, double lined O-type spectroscopic binary were analyzed. Archival data from IUE (17 spectra well distributed in orbital phase) were analyzed with several techniques. A cross correlation analysis, which showed that the secondary produces significant lines in the UV, indicate…
Preliminary Analysis of an Ultraviolet Hubble Space Telescope Faint Object Camera Image of the Center of M31
Boksenberg, A.; Barbieri, C.; Weigelt, G. +17 more
A 5161 s exposure was taken with the FOC on the central 44" of M31, through a filter centered at 1750 A. Much of the light is redleak from visible wavelengths, but nearly half of it is genuine UV. The image shows the same central peak found earlier by Stratoscope, with a somewhat steeper dropoff outside that peak. More than 100 individual objects …