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An Atlas of Ultraviolet Spectra of Star-forming Galaxies
Panagia, N.; Calzetti, D.; Wyse, Rosemary F. G. +2 more
An atlas of ultraviolet spectra of the central regions of 143 spiral, irregular, blue compact, Seyfert 2, and starburst galaxies is produced by combining 387 low-resolution spectra from the IUE data archives. The spectra have been extracted with an optimal algorithm and co-added to produce spectra with the best possible signal-to-noise ratio. Our …
Discovery of Jovian dust streams and interstellar grains by the Ulysses spacecraft
Forsyth, R.; Balogh, A.; Bame, S. J. +20 more
ON 8 February 1992, the Ulysses spacecraft flew by Jupiter at a distance of 5.4 AU from the Sun. During the encounter, the spacecraft was deflected into a new orbit, inclined at about 80° to the ecliptic plane, which will ultimately lead Ulysses over the polar regions of the Sun1. Within 1 AU from Jupiter, the onboard dust de…
SN 1991bg: A Type IA Supernova With a Difference
Suntzeff, N. B.; Walker, A. R.; Caldwell, Nelson +28 more
We present 13 spectra and 31 photometric observations covering the first 150 days of SN 1991bg in NGC 4374 (M 84). Although SN 1991bg was a type Ia supernova displaying the characteristic Si II absorption at 6150 A near maximum and the Fe emission lines at late phases, it varied from the well-defined norm for SNe Ia in several important respects. …
Hubble Space Telescope Discovery of Candidate Young Globular Clusters in the Merger Remnant NGC 7252
Robert, Carmelle; Leitherer, Claus; Whitmore, Bradley C. +2 more
New, high-resolution images of the central region of NGC 7252 obtained with the Planetary Camera of the Hubble Space Telescope are presented. NGC 7252 (sometimes referred to as the "Atoms-for-Peace" Galaxy) is a prototypical example of a remnant of two merged disk galaxies. Our most striking result is the discovery of a population of about 40 blue…
Goddard High-Resolution Spectrograph Observations of the Local Interstellar Medium and the Deuterium/Hydrogen Ratio along the Line of Sight toward Capella
Ayres, Thomas R.; Savage, Blair D.; Brown, Alexander +6 more
HST Goddard High-Resolution Spectrograph observations of the 1216, 2600, and 2800 A spectral regions are analyzed for the spectroscopic binary system Capella, obtained at orbital phase 0.26 with 3.27-3.57 km/s resolution and high SNR. The column densities of H I, D I, Mg II, and Fe II for the local interstellar medium along this 12.5 pc line of si…
Detection of Interstellar Pick-Up Hydrogen in the Solar System
Balsiger, H.; Geiss, J.; Galvin, A. B. +6 more
Interstellar hydrogen ionized primarily by the solar wind has been detected by the SWICS instrument on the Ulysses spacecraft at a distance of 4.8 astronomical units from the sun. This "pick-up" hydrogen is identified by its distinct velocity distribution function, which drops abruptly at twice the local solar wind speed. From the measured fluxes …
The Hubble Space Telescope Quasar Absorption Line Key Project. I. First Observational Results, Including Lyman-Alpha and Lyman-Limit Systems
Turnshek, David A.; Schneider, Donald P.; Savage, Blair D. +9 more
We present spectra for a total of 37 quasars with small and moderate redshifts; the quasars were observed with the Faint Object Spectrograph of the Hubble Space Telescope. The spectra are obtained either at a resolution of R = 1300 (hereafter "higher resolution") or a resolution of r = 180 (hereafter "lower resolution"). We report new higher resol…
Mechanism for the acceleration and ejection of dust grains from Jupiter's magnetosphere
Horanyi, M.; Grun, E.; Morfill, G.
PERHAPS the most unexpected finding of the Ulysses mission so far has been the detection of quasi-periodic streams of high-velocity, submicrometre-sized dust particles during the spacecraft's encounter with Jupiter1. The impact geometry clearly shows that these small grains originate in the jovian system, but it is surprising that any d…
Early-Type Galaxies, Dark Halos, and Gravitational Lensing Statistics
Maoz, Dan; Rix, Hans-Walter
We present calculations of the expected statistics of gravitational lensing of quasars in the Hubble Space Telescope snapshot survey. We first model early-type (elliptical and SO) galaxies using their observed surface brightness profiles and dynamically inferred mass-to-light ratios. Our work improves upon previous calculations, which have general…
Composition of Interstellar Clouds in the Disk and Halo. I. HD 93521
Fitzpatrick, Edward L.; Spitzer, Lyman, Jr.
Interstellar column densities of Fe, S, Si, Mn, and Mg in their dominant ionization state, as well as of C(+) and S(2+), are presently derived from analyses of HST UV observations of the Galactic halo star HD 93521. Ratios of column densities for the dominant species yield approximations of the logarithmic depletion D(X) in the warm, primarily neu…