Search Publications
Observations of the Gaseous Galactic Halo toward 3C 273 with the Goddard High Resolution Spectrograph
Savage, Blair D.; Morris, Simon L.; Gilliland, Ronald L. +2 more
We present an analysis of observations of 24 absorption lines produced zero redshift by Milky Way disk and halo gas along the sight line to 3C 273. The observations were obtained with the intermediate-resolution mode of the Goddard High Resolution Spectrograph (GHRS) using the large entrance aperture. The spectral spread function has FWHM ~20 km s…
The Narrow-Line Region of High-Luminosity Active Galactic Nuclei
Netzer, H.; Ferland, G. J.; Browne, I. W. A. +5 more
The HST's Faint Object Spectrograph and Kitt Peak ground instruments have been used to gather high S/N spectroscopic observations of seven radio-loud quasars; the resolutions obtained allow a separation of emission line broad and narrow components to be made. Attention is given to the relative weakness of the narrow UV lines, in contradiction to t…
Observations of the White Dwarf in the U Geminorum System with the Hopkins Ultraviolet Telescope
Blair, William P.; Sion, Edward M.; Kriss, Gerard A. +4 more
The Hopkins Ultraviolet Telescope was used to obtain an FUV spectrum of U Gem about 10 d after the end of an outburst. Most of the FUV emission from U Gem appears to rise from the white dwarf (WD) in the system. Various possibilities to explain the hot component in the present spectrum are explored. It is most likely due to radiation from the boun…
The Interstellar Abundances of Tin and Four Other Heavy Elements
York, D. G.; Welty, D. E.; Hobbs, L. M. +2 more
Spectra recorded at 1150-1600 A with an instrumental resolution near 16 km/s were obtained with the Goddard High-Resolution Spectrograph on board the HST. The gaseous interstellar abundances of five heavy elements along the light paths to 23 Ori, 15 Mon, 1 Sco, Pi Sco, and Pi Aqr were determined from the observations. The 1400.450 A line of Sn II …
Impulsive bursts of relativistic electrons discovered during Ulysses' traversal of Jupiter's dusk-side magnetosphere
Simpson, J. A.; McKibben, R. B.; Zhang, M.
During its flyby of Jupiter in February 1992, the Ulysses spacecraft passed through the Southern Hemisphere dusk-side Jovian magnetosphere, a region not previously explored by spacecraft. Among the new findings in this region were numerous, sometimes periodic, bursts of high energy electrons with energies extending from less than 1.5 MeV to beyond…
Environment dependence of interstellar extinction curves.
Greenberg, J. M.; Jenniskens, P.
The IUE interstellar extinction curves published by Aiello et al. (1988) are decomposed into a bump, linear rise and FUV non-linear rise, in the parameterization scheme of Fitzpatrick & Massa (1990). The parameters of the 115 extinction curves are given. The lines of sight are characterized from the IRAS Skyflux and Point Source Catalogue data…
Dust particle impacts during the Giotto encounter with comet Grigg-Skjellerup
Colangeli, L.; Green, S. F.; Greenberg, J. M. +7 more
IN the European Space Agency's 1992 Giotto Extended Mission, the Dust Impact Detection System operated successfully during a fly-by that took the spacecraft within about 200 km of the nucleus of comet Grigg-Skjellerup. During the encounter, three meteoroid impacts were detected on Giotto's front shield. The particle masses were found to be lOO
Two New Extremely Iron-rich Hot DA White Dwarfs and the Nature of the EUV Opacity
Werner, K.; Dreizler, S.; Barstow, M. A. +8 more
We have obtained IUE echelle spectra of two bright extreme ultraviolet (EUV) sources discovered by the ROSAT wide field camera all-sky survey. These stars, RE 2214-492 and RE 0623-377, are previously uncataloged hot DA white dwarfs with respective apparent visual magnitudes of 11.71 and 12.09 and exhibit short-wavelength EUV cutoffs steeper than m…
Detection of the local interstellar cloud from high-resolution spectra of nearby stars: Inferences on the heliospheric interface
Ferlet, R.; Vidal-Madjar, A.; Lallement, R. +1 more
High-resolution spectroscopic observations of the local interstellar medium between the Sun and nearby stars have been recorded with the Aurelie spectrometer of the Observatoire de Haute Provence (France). They have been used to identify and characterize the local interstellar cloud (LIC) in which the Sun is embedded. The ``Doppler triangulation''…
Gravitational Lensing Statistics Based on a Large Sample of Highly Luminous Quasars
Magain, P.; Filippenko, A. V.; Surdej, J. +6 more
Results on gravitational lensing statistics applied to a sample of 469 highly luminous quasars are reported. The objects were directly imaged, either from the ground (ESO, CFH) under optimal seeing conditions, or using the Hubble Space Telescope. We have derived values for the effectiveness parameter F of galaxies, modeled by means of singular iso…