Search Publications
Dust Extinction of the Stellar Continua in Starburst Galaxies: The Ultraviolet and Optical Extinction Law
Calzetti, Daniela; Storchi-Bergmann, Thaisa; Kinney, Anne L.
We analyze the IUE UV and the optical spectra of 39 starburst and blue compact galaxies in order to study the average properties of dust extinction in extended regions of galaxies. The optical spectra have been obtained using an aperture which matches that of IUE, so comparable regions within each galaxy are sampled. The data from the 39 galaxies …
R v-dependent Optical and Near-Ultraviolet Extinction
O'Donnell, James E.
We have derived extinctions A(lambda)/A(V) at the wavelengths of the uvby filters for 22 stars, with a range of values of Rnu, from the sample of Cardelli, Clayton, & Mathis (1989, hereafter CCM). We have fit these extinctions, and also UBVRIJHKL, IUE and ANS extinction measurements, with linear relations A(lambda)/A/(V) = a+b/R
Multiwavelength Tests of the Dusty Torus Model for Seyfert Galaxies
Mulchaey, John S.; Wilson, Andrew S.; Kinney, Anne L. +5 more
We present a compilation of emission properties for a sample of 116 Seyfert galaxies based on both previously unpublished data and measurements available in the literature. These measurements include fluxes in the emission lines [O III] λ5007 and Hβ, as well as the infrared (25-60 microns), ultraviolet (1450 A), soft (0.2-4 keV), and hard (2-10 ke…
An IUE Survey of Interstellar H i Lyman-Alpha Absorption. II. Interpretations
Savage, Blair D.; Diplas, Athanassios
We present an analysis of interstellar neutral hydrogen column densities obtained from archival Ly alpha absorption line data toward the complete sample of B2 and hotter stars observed at high spectral resolution with the IUE satellite. The full sample includes 554 stars and more than doubles the number of lines of sight previously observed. Many …
Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. V. Variability of the Ultraviolet Continuum and Emission Lines of NGC 3783
Altieri, B.; Mazeh, T.; Shull, J. M. +61 more
We report on the results of intensive ultraviolet spectral monitoring of the Seyfert 1 galaxy NGC 3783. The nucleus of NGC 3783 was observed with the International Ultraviolet Explorer satellite on a regular basis for a total of 7 months, once every 4 days for the first 172 days and once every other day for the final 50 days. Significant variabili…
The Balmer-dominated Northeast Limb of the Cygnus Loop Supernova Remnant
Blair, William P.; Raymond, John C.; Hester, J. Jeff
We present a comprehensive investigation of the Balmar-dominated northeast limb of the Cygnus Loop supernova remnant. Data presented include H alpha (O III), and X-ray images, UV and visible spectrophotometry, and high-resolution spectroscopy. The two relatively bright Balmer-dominated filaments visible on the POSS prints are seen to be part of a …
The 1993 Multiwavelength Campaign on 3C 279: The Radio to Gamma-Ray Energy Distribution in Low State
Maraschi, L.; Ghisellini, G.; Pian, E. +27 more
Simultaneous observations of 3C 279 at radio, millimeter, near- infrared, optical, ultraviolet (with IUE) and X-ray (with ROSAT) wavelengths were obtained in 1992 December-1993 January, during a three week pointing at the source by the Compton Gamma Ray Observatory. The blazar was in a quiescent or "low" state during this period. Comparing the mul…
A Spectroscopic Analysis of DAO and Hot DA White Dwarfs: The Implications of the Presence of Helium and the Nature of DAO Stars
Fontaine, G.; Bergeron, P.; Wesemael, F. +4 more
A comprehensive study of optical spectrophotometry of DAO white dwarfs is presented. A detailed analysis of the He II lambda 4686 line profiles demonstrates conclusively that the chemical composition in the atmospheres of DAO stars is not stratified, except in one object (PG 1305-017). On the other hand, line profiles calculated from models with h…
Luminosity Effects and the Emission-Line Properties of Quasars with 0 < Z < 3.8
Green, Richard F.; Osmer, Patrick S.; Porter, Alain C.
We present data and a spectral atlas for 76 quasars with 2.97 < z < 3.80 and for 33 quasars with z ~ 2, together with measures of 73 quasars from the IUE archives that mostly have z < 1. The quasars provide a sampling of the luminosity-redshift plane at constant luminosity for 0 < z < 3.8, a range of a factor of 40 in luminosity for…
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…