Search Publications
The Far-Ultraviolet Spectra of Early-Type Galaxies
Lauer, Tod R.; Faber, S. M.; Burstein, David +2 more
New and revised ultraviolet erergy distributions are presented based on 97 IUE spectra of 31 early-type galaxies and the bulge of M31. Measurements of the line strength index Mg_2_ and the V magnitude flux with the IUE aperture are included. The average flux between 1250 and 1850 A is combined with the V magnitude to form an ultraviolet/optical (1…
The X-Ray Spectral Properties of Accretion Disks in X-Ray Binaries
Stella, L.; Parmar, A. N.; White, N. E.
Using EXOSAT observations, the spectral properties of the persistent emission from a number of X-ray burst sources, high-luminosity low-mass X-ray binaries (LMXRB), and galactic black hole candidates are compared with various models for X-ray emission from an accretion disk surrounding a compact object in a binary system. These models include the …
Galactic Evolution and Cosmology: Probing the Cosmological Deceleration Parameter
Takahara, Fumio; Yoshii, Yuzuru
The magnitude-redshift relation, the color-redshift relation, the galaxy number count, the redshift distribution of galaxies, and the extragalactic background light are calculated taking into account the effect of galactic evolution for several values of the cosmological deceleration parameter q_0_ and the redshift of galaxy formation z_F_. The sp…
An Analysis of the Shapes of Ultraviolet Extinction Curves. II. The Far-UV Extinction
Fitzpatrick, Edward L.; Massa, Derck
In this paper we examine the properties of interstellar extinction in the far-ultraviolet region (FUV; λ < 1700 A) utilizing IUE extinction curves for a primary data sample of 45 reddened Milky Way OB stars. These results are combined with those derived for the 2175 A bump in a previous study. We find that IUE extinction curves can be represent…
Spectral Synthesis in the Ultraviolet. II. Stellar Populations and Star Formation in Blue Compact Galaxies
O'Connell, Robert W.; Thuan, Trinh X.; Fanelli, Michael N.
Far-UV spectra of seven blue compact galaxies have been obtained with the IUE satellite. These objects span a range in luminosity of -21 <= M_B_ <= -13. We have investigated their stellar content and star formation history by applying the technique of optimizing population synthesis utilizing the library of far-UV stellar spectra developed b…
The Fluorescence of Cometary OH
A'Hearn, Michael F.; Schleicher, David G.
A new solar spectral atlas, improved oscillator strengths, and additional transitions have been incorporated in calculations of the fluorescent equilibrium of the OH molecule in comets as a function of heliocentric distance and radial velocity. Comparisons of detailed, ultraviolet band profiles have been made with the observed, high-resolution spe…
Spatial and Spectral Interpretation of a Bright Filament in the Cygnus Loop
Gull, T. R.; Raymond, J. C.; Hester, J. J. +3 more
A comparison is made of optical and UV line intensities and spatial and spectral optical line profiles of a well-defined Cygnus Loop filament with theoretical models. It is found that the sharp filament is due to the tangency to the line of sight of a large, thick sheet of emitting gas. The emitting region associated with the spur is very deep, an…
Two Lines of Sight with Exceedingly Anomalous Ultraviolet Interstellar Extinction
Savage, Blair D.; Cardelli, Jason A.
Low-resolution IUE data obtained toward HD 62542, a B5 V star in a line of sight associated with a dark cloud in the Gum nebula region near ζ Pup and γ Vel, yield an extinction curve with an extremely broad and weak UV extinction bump and the highest far-UV extinction yet observed in the Milky Way, reaching a value of E(1200-V)/E(B-V) ≈ 15. The we…
Lyman- alpha Emission in Star-forming Galaxies
Huchra, John P.; Geller, Margaret J.; O'Brien, Paul +2 more
We report IUE observations of five blue, low-metallicity, star-forming galaxies sufficiently redshifted to permit detection of Lyα. Two of the galaxies exhibit Lyα emission at modest levels far below the recombination limit; two objects have Lyα in absorption. These observations confirm and extend earlier work which indicates that relatively unevo…
Galactic Interstellar Abundance Surveys with IUE. III. Silicon, Manganese, Iron, Sulfur, and Zinc
Shull, J. Michael; van Steenberg, Michael E.
This paper continues a survey of intestellar densities, abundances, and cloud structure in the Galaxy using the IUE satellite. A statistical data set of 223 O3-B2.5 stars is constructed, including 53 stars in the Galactic halo. It is found that S II lines in B stars, of luminosity classes IV and V, have possible contamination from stellar S II, pa…