Search Publications
Detection of [O ii] lambda 2471 from the Io Plasma Torus
Feldman, P. D.; Moos, H. W.; Strobel, D. F. +2 more
We report the first detection of the O II 2471-A forbidden line from the Io plasma torus. Observations of the east and west torus ansae at 5.7 R(J) on 1992 March 15 and May 1, respectively, using the Goddard High Resolution Spectrograph of the HST have resulted in about 5-sigma detections of the line on both occasions, with line brightnesses of 30…
The Spectrum of the Central Star of the Planetary Nebula in M22
Harrington, J. P.; Paltoglou, George
New optical observations of the central star of the planetary nebula IRAS 18333-2357 in the globular cluster M22 show lines of H I, He II, C IV, N IV, and N V. The spectrum closely resembles the sdO star KS 292, which has surface abundances enhanced by products of hydrogen shell burning and helium burning, and an effective temperature of 75,000 K.…
Hubble Space Telescope Ultraviolet Spectroscopy of the Highly Polarized but Quiescent Quasar OI 287
Kinney, Anne L.; Antonucci, Robert; Hurt, Todd
The quasar OI 287 has a unique combination of properties, including a high and constant optical polarization oriented parallel to the radio axis, a quiescent optical flux, and a lobe-dominant radio source. The polarization suggests a relationship to the broad absorption line quasars. It is a possible transition object which could illuminate the ge…
Optical and Hubble Space Telescope Ultraviolet Spectropolarimetry of 3C 273 and PG 1114+445
Schmidt, Gary D.; Smith, Paul S.; Allen, Richard G.
Ultraviolet polarization measurements of 3C 273 made with the Faint Object Spectrograph of the Hubble Space Telescope are combined with new optical spectropolarimetry and broad-band measurements made during occasions when the linear polarization of the quasar was <=1%. The HST measurements exhibit very weak UV polarization during the epoch of o…
The Ultraviolet Absorption Spectrum of the Quasar PKS 0405-12 and the Local Density of Lyman-Alpha Absorption Systems
Schneider, Donald P.; Jannuzi, Buell T.; Bahcall, John N. +1 more
A sample of 32 absorption lines has been identified in the ultraviolet spectrum of the z = 0.57 quasar PKS 0405 - 12. The observations were obtained using three R = 1300 gratings of the Faint Object Spectrograph of the Hubble Space Telescope. The data cover the wavelength range 1190- 3260 A. The sample was constructed by requiring that all include…
JHK Photometry of WD 0950+139
Liebert, James; Fulbright, Michael S.
We present results from several nights of JHK photometry of the hot DA white dwarf 0950+139. It has a significant infrared excess over the expected flux from the white dwarf alone, confirming a previous finding by Zuckerman et al. (1991). The infrared excess corresponds to an upper limit on the spectral type of a companion of M4 V. We consider two…
Extreme Ultraviolet Observations of HZ 43 and the Local H/He Ratio with the Hopkins Ultraviolet Telescope
Feldman, Paul D.; Kimble, Randy A.; Davidsen, Arthur F. +1 more
We present a spectrum of the hot DA white dwarf HZ 43 in the EUV, near the 504-A ionization edge of neutral helium, obtained with the Hopkins Ultraviolet Telescope (HUT) during the 1990 December Astro-1 mission. The interstellar column densities derived from this spectrum rule out the anomalous interstellar absorption model proposed by Heise et al…
Colliding Wind Binary Systems: Monte Carlo Simulations of Line-Profile Variability
Stevens, Ian R.
We investigate the line-profile variability observed in colliding wind binary systems. In these systems the ultraviolet P Cygni line profiles show marked orbital variability; the nature of which differs between individual lines and binaries. We present results of three-dimensional Monte Carlo simulations of the radiative transfer and line formatio…
30 Doradus: Ultraviolet and Optical Stellar Photometry
Cheng, Kwang-Ping; O'Connell, Robert W.; Bohlin, Ralph C. +7 more
Stellar photometry is presented for 314 stars in a 9.7' x 9.7' field in the 30 Dor nebula centered on R136. Magnitudes are computed from Ultraviolet Imaging Telescope images in up to 4 bands with effective wave-lengths from 1615 to 2558 A, and from a ground-based CCD image in the B band. Spectral types and extinctions are estimated using a least- …
The First Detection of a Collapsed Core Globular Cluster in M31
Cacciari, C.; Federici, L.; Ferraro, F. R. +6 more
We report on the observations of a globular cluster (designated G105 = Bo 343) in the nearby spiral galaxy M 31, using the Hubble Space Telescope (HST). Image deconvolutions using three different methods indicate that this cluster has a density profile with the morphology characteristic of stellar systems which have undergone core collapse, i.e., …