Search Publications
The Abundance of Heavy Elements in Interstellar Gas
Cardelli, Jason A.
The Goddard high-resolution spectrograph aboard the Hubble Space Telescope has been used to produce interstellar abundance measures of gallium, germanium, arsenic, krypton, tin, thallium, and lead, the heaviest elements detected in interstellar gas. These heavy elements arise from stellar nuclear processes (slow- and rapid-process neutron capture)…
Geometry and Physical Conditions in the Stellar Wind of AG Carinae
Drissen, Laurent; Robert, Carmelle; Leitherer, Claus +8 more
AG Carinae is one of the prototypes of the class of Luminous Blue Variables (LBVs). Since 1990 the star has continuously brightened in its visual continuum. We report on a multi-instrument and -wavelength observing campaign to monitor the current activity phase of AG Car. Ground-based photometry, polarimetry, spectroscopy, and space-ultraviolet sp…
Hubble Space Telescope Photometry of the Central Regions of Virgo Cluster Elliptical Galaxies. II. Isophote Shapes
van den Bosch, Frank C.; O'Connell, Robert W.; Ferrarese, Laura +2 more
The isophotal shapes of a magnitude limited sample of Virgo ellipticals are presented. These are derived from high resolution HST photometry. The absence of atmospheric seeing and accurate knowledge of the PSF allows us to perform an accurate deconvolution. Model galaxies were constructed to test the deconvolution algorithms used, and showed that …
The Hubble Space Telescope Quasar Absorption Line Key Project. VI. Properties of the Metal-rich Systems
Turnshek, David A.; Petitjean, Patrick; Schneider, Donald P. +10 more
We present an analysis of the properties of a sample of 18 metal-rich, low-redshift z_abs_ < z_em_ absorbers seen in low- and medium-resolution spectra obtained for the Quasar Absorption Line Key Project with the Hubble Space Telescope Faint Object Spectrograph. For most of the C IV and Lyman-limit systems, observations in the optical wavelengt…
Detection of the SO2 Atmosphere on Io with the Hubble Space Telescope
Feldman, P. D.; Moos, H. W.; Ballester, G. E. +3 more
Observations of the trailing hemisphere of Io made with the Faint Object Spectrograph of the Hubble Space Telescope in March 1992 have resulted in the first detection of atmospheric SO2 absorption bands in the ultraviolet. These observations represent only the third positive means of detection of what is widely believed to be Io's prima…
Solar Flux Variability and the Lifetimes of Cometary H 2O and OH
Feldman, P. D.; Festou, M. C.; Budzien, S. A.
The far and extreme ultraviolet (FUV/EUV) solar flux determines the photodestruction rates of H2O and OH in cometary comae and affects their spatial density distributions. Between the minimum and maximum of the solar activity cycle, the solar flux varies by as much as a factor of 2-3 at some FUV and EUV wavelengths. From recent cross se…
HST Ultraviolet Spectropolarimetry of NGC 1068
Antonucci, Robert; Hurt, Todd; Miller, Joseph
We present multiaperture spectropolarimetric observations of the Seyfert 2 galaxy NGC 1068. The nuclear region of NGC 1068 was observed with three apertures 4.3" x 1.4", 1.0" and 0.3") by the Hubble Space Telescope. These ultraviolet data allow us to study the scattered, nuclear light without the complication of polarization dilution caused by str…
Detection of CO Cameron Band Emission in Comet P/Hartley 2 (1991 XV) with the Hubble Space Telescope
Feldman, P. D.; A'Hearn, M. F.; Weaver, H. A. +3 more
Ultraviolet (UV) spectra of comet P/Hartley 2 (1991 XV) taken with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope (HST) in 1991 September reveal several bands of the Cameron system of CO (a 3 Pi-X 1 Sigma). These band are most likely due to 'prompt' emission from CO2 and, thus, provide a direct tracer of the CO2 abundance in the…
The Ultraviolet Emission Properties of Five Low-Redshift Active Galactic Nuclei at High Signal-to-Noise Ratio and Spectral Resolution
Laor, Ari; Schneider, Donald P.; Green, Richard F. +3 more
We analyze the ultraviolet (UV) emission line and continuum properties of five low-redshift active galactic nuclei (four luminous quasars: PKS 0405 - 123, H1821 +643, PG 0953+414, and 3C 273, and one bright Seyfert 1 galaxy: Mrk 205). The HST spectra have higher signal-to-noise ratios (typically ~60 per resolution element) and spectral resolution …
HST Images of Very Compact Blue Galaxies at Z approximately 0.2
Bershady, Matthew A.; Majewski, Steven R.; Koo, David C. +2 more
We present the results of HST Wide-Field Camera (WFC) imaging of seven very compact, very blue galaxies with B <= 21 and redshifts z ~ 0.1 to 0.35. Based on deconvolved images, we estimate typical half-light diameters of ~0.65", corresponding to ~1.4 h^-1^ kpc at redshifts z~0.2. The average rest frame surface brightness within this diameter is…