Search Publications
Radiative Levitation in Hot White Dwarfs: Equilibrium Theory
Chayer, P.; Fontaine, G.; Wesemael, F.
We present the results of detailed calculations of radiative levitation in hot white dwarfs using the extensive and homogeneous atomic data given in TOPBASE. Radiative accelerations and equilibrium abundances have been computed for C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, and Fe on grids of pure hydrogen and pure helium stellar envelope models. The…
Ultraviolet to Near-Infrared Spectral Distributions of Star-forming and Seyfert 2 Galaxies
Storchi-Bergmann, Thaisa; Challis, Peter; Kinney, Anne L.
Combined UV, optical and near-IR spectral distributions of a sample of 48 southern star-forming and Seyfert 2 galaxies are presented. The optical and near-IR spectra were obtained using apertures matching those of the UV observations (10" X 20") and in most cases correspond to the bulk of the gas and stellar population contribution from the whole …
Atlas of Synthetic Ultraviolet Spectra of Massive Star Populations
Robert, Carmelle; Heckman, Timothy M.; Leitherer, Claus
An atlas of synthetic ultraviolet spectra of a population of massive stars is presented. The spectra are based on a stellar library of lUE high-dispersion spectra of O and Wolf-Rayet stars, coupled to an evolutionary synthesis code. Later spectral types are included via low-dispersion spectra. Line profiles of N V λ1240, Si IV λ1400, C IV λ1550, H…
The RIASS Coronathon: Joint X-Ray and Ultraviolet Observations of Normal F--K Stars
Schmitt, J. H. M. M.; Ayres, Thomas R.; Mas-Hesse, J. M. +21 more
Between 1990 August and 1991 January the ROSAT/IUE All Sky Survey (RIASS) coordinated pointings by the International Ultraviolet Explorer (IUE) with the continuous X-ray/EUV mapping by the Roentgensatellit (ROSAT). The campaign provided an unprecedented multiwavelength view of a wide variety of cosmic sources. We report findings for F-K stars, a l…
The Ultraviolet Emission Properties of 13 Quasars
Laor, Ari; Schneider, Donald P.; Green, Richard F. +2 more
We analyze the ultraviolet (UV) emission properties of a sample of 13 quasars studied with the Hubble Space Telescope (HST). The quasars redshifts are in the range 0.165 <= z <= 2.06, and their absolute magnitudes are in the range -30.1 <= M_v_ <= -24.4. The data were obtained with the Faint Object Spectrograph and have a spectral reso…
Ultraviolet Observations of SN 1987A with the IUE Satellite
Pun, Chun S. J.; Cassatella, Angelo; Gilmozzi, Roberto +12 more
Ultraviolet (λ: 1150-3300 A) observations of SN 1987A with the IUE satellite provide a unique data set. Observations started the day after discovery, 1987 February 24 (day 1.6), and a total of 751 spectra were obtained through 1992 June 9 (day 1567). The data have been processed to generate a complete catalog of SN 1987A ultraviolet spectra. The d…
Multifrequency Spectra of EXOSAT Blazars
Ghosh, K. K.; Soundararajaperumal, S.
Blazars have been divided into two groups: radio-selected blazars (RBLs) and X-ray-selected blazars (XBLs). Results of the X-ray spectral analysis of 28 such blazars which were observed with EXOSAT are presented in this paper, and in four these are new results which were not published earlier. X-ray results suggest that XBLs are steep-spectrum sou…
A Catalog of Far-Ultraviolet Point Sources Detected with the FAUST Telescope on ATLAS-1
Bowyer, Stuart; Lampton, Michael; Sasseen, Timothy P. +1 more
We list the photometric measurements of point sources made by the Far Ultraviolet Space Telescope (FAUST) when it flew on the ATLAS-1 space shuttle mission. The list contains 4698 Galactic and extragalactic objects detected in 22 wide-field images of the sky. At the locations surveyed, this catalog reaches a limiting magnitude approximately a fact…
C IV and O VI Transitions in the Region lambda lambda 1100--2000 and Examples Found in IUE Spectra of Hot Stars
Feibelman, Walter A.; Johansson, Sveneric
We present Ritz wavelengths for more than 130 transitions of C IV and O VI in the range λλ1100-2000 and show examples of absorption features as seen in representative examples of high-dispersion IUE spectra of very hot (∼100,000 K) nuclei of planetary nebulae, white dwarfs, and PG 1159-type stars. The regions near He II λ640 and interstellar Si II…
Ultraviolet and Optical Observations of OB Associations in M31
O'Connell, R. W.; Bohlin, R. C.; Stecher, T. P. +7 more
Images of the central and southern parts of the local group Sb spiral galaxy M31 were obtained by the Ultraviolet Imaging Telescope during the Astro-1 Spacelab mission. Stellar photometry is obtained for 611 stars in 59 van den Bergh associations in the near-UV A1 band (central wavelength 2490 A), and for 130 of these stars in the far-UV B1 band (…