Search Publications

Atlas of Quasar Energy Distributions

Elvis, Martin; Wilkes, Belinda J.; McDowell, Jonathan C. +6 more

We present an atlas of the spectral energy distributions (SEDs) of normal, nonblazar, quasars over the whole available range (radio to 10 keV X-rays) of the electromagnetic spectrum. The primary (UVSX) sample includes 47 quasars for which the spectral energy distributions include X-ray spectral indices and UV data. Of these, 29 are radio quiet, an…

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 R_nu, 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

Elemental abundances for a sample of southern galactic planetary nebulae.

Barlow, M. J.; Kingsburgh, R. L.

We present spectrophotometric observations of a sample of 80 southern galactic planetary nebulae (PN), and derive elemental abundances for 68 objects, supplementing the optical observations with Uv data in 25 cases. We define Type I PN as those objects that have experienced envelope-burning conversion to nitrogen of dredged- up primary carbon. Suc…

Thick tori around active galactic nuclei: a comparison of model predictions with observations of the infrared continuum and silicate features.

Danese, L.; Granato, G. L.

The continuum expected from active galactic nuclei (AGN) surrounded by thick tori is compared to the data available for a sample of optically selected Seyfert 1 galaxies. The optical and near-IR nuclear fluxes have previously been derived for these objects, and hence the spectral energy distributions (SEDs) of their active nuclei can be analysed. …

An IUE Survey of Interstellar H i LY alpha Absorption. I. Column Densities

Savage, Blair D.; Diplas, Athanassios

We measure Galactic interstellar neutral hydrogen column densities by analyzing archival interstellar Ly alpha absorption line data toward 554 B2 and hotter stars observed at high resolution with the IUE satellite. This study more than doubles the number of lines of sight with measures of N(H I) based on Ly alpha. We have included the scattered li…

Massive Star Populations in Nearby Galaxies

Conti, Peter S.; Maeder, André

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 …

Radiation-driven winds of hot luminous stars. XII. A first step towards detailed UV-line diagnostics of O-stars.

Butler, K.; Kudritzki, R. P.; Pauldrach, A. W. A. +2 more

Improved radiation driven wind models are constructed to calculate detailed synthetic UV spectra of hot luminous stars. The model improvements comprise: a very detailed multilevel non-local thermodynamic equilibrium (NLTE) treatment of 29 of the most important ionization stages, in particular C, N, O and Fe using accurate atomic data; the approxim…