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New EXOSAT Results from the Intermediate Polar V1223-SAGITTARIUS
Beuermann, K.; Osborne, J. P.; Mason, K. O. +1 more
We report new results obtained from the EXOSAT AO- 1 observation of the intermediate polar V1223 Sgr. The detection of a 12.4 minute period in the medium energy X-ray flux with an associated hardness ratio variation has been previously reported in Osborne et al. (1984a). Further work has revealed: a narrow dip at the phase zero in the folded mediu…
Abundances of O, Mg, S, Cr, Mn, Ti, NI and Zn from absorption lines of neutral gas in the Large Magellanic Cloud in front of R 136.
Savage, B. D.; de Boer, K. S.; Fitzpatrick, E. L.
The authors have searched six high-dispersion IUE spectra of R136 for weak absorption lines of C I, O I, Mg I, Mg II, Si I, Si II, P I, Cl I, Cr II, Mn II, Fe I, Ni II, Zn II, CO and C2. The absorption detected is from neutral gas in front of the 30 Doradus H II region. For the first time abundances of Mg, Cr, Mn, Ti, Ni, and Zn are det…
Detection and analysis of photospheric CNO features in the ultraviolet spectrum of the hot DO white dwarf PG 1034+001.
Sion, E. M.; Wesemael, F.; Liebert, J.
An analysis of PG 1034 + 001 extended to include the high-dispersion IUE spectra and the high-resolution optical multiple-mirror telescope echelle spectra is discussed. The observations reveal the presence of absorption lines (C IV at 1548 and 1551 A, N V at 1238 and 1242 A, and O V at 1371 A) from highly ionized species with large redshifts (+ 40…
Ultraviolet absorption by highly ionized halo gas near the galactic center.
Savage, B. D.; Massa, D.
As part of a program to survey highly ionized gas in the Milky Way disk and halo, the authors have obtained high-resolution IUE far-UV spectra of 12 stars at galactocentric distances less than 6 kpc. The stars are 0.7 - 2.2 kpc away from the plane. Most of the spectra contain exceedingly strong and broad interstellar absorption lines of weakly and…
Magnetic structure in cool stars. VIII. The MG II H and K surface fluxes in relation to the MT Wilson photometric CA II H and K measurements.
Zwaan, C.; Oranje, B. J.
Data from IUE observations of 14 F, G, and K stars of luminosity II-V in the Mg II h + k lines are presented in tables and compared with published Mt. Wilson photometry of the Ca II H + K lines, and empirical relations are derived to facilitate the use of Ca II H + K data in investigating the chromospheric structure of cool stars. The results are …
The ultraviolet spectra of normal elliptical galaxies : a population synthesis approach.
Perola, G. C.; Nesci, R.
Published UV spectra of elliptical galaxies are compared with the results of population syntheses (based on HB stars, accreting white dwarfs in binary systems, or young stars forming in bursts) in an attempt to explain the observed upturn shortward of 200 nm. The results are presented in tables and spectra and discussed in detail. Good agreement i…
EXOSAT observations of active galactic nuclei
McHardy, I.; Branduardi-Raymont, G.; Molteni, D. +3 more
EXOSAT observations of the Type 1 Seyfert galaxies NGC3783 and NGC5548 are reported. Contrary to previous findings, the X-ray spectrum of NGC3783 is not heavily cutoff at low energies. This suggest that the conditions of the broad-line region in NGC3783 are different from those in which the earlier data were obtained. We speculate on the presence …
Dwarf novae in outburst : simultaneous ultraviolet and optical observations of VW Hydri.
Verbunt, F.; Schwarzenberg-Czerny, A.; Ward, M. +4 more
The authors present simultaneous spectrophotometry of the dwarf nova VW Hydri in the range 1200 - 7000 Å. The main set of observations cover one complete outburst, including the rise and the decline. Comparing these data with data from other outbursts of VW Hyi it is found that all the data can be interleaved. This underlines the similarity in the…
Large Magellanic CLOUD-X-4 - 13.4 Pulsations and an X-Ray Flare Observed by EXOSAT
Pietsch, W.; Pakull, M.; Staubert, R. +1 more
EXOSAT observed LMC X-4 on November 17/19, 1983 for one 1.4 day binary period during the high state of the 30.5 day cycle. An eclipse with sharp ingress and slow egress was detected with an eclipse angle of 27.1±1.0 dgr. In the medium energy experiment the source showed a hard power law spectrum. Outside eclipse the source was remarkably constant …
Studies of hot B subdwarfs. III. Carbon, nitrogen and silicon abundances in three sdB stars.
Fontaine, G.; Sion, E. M.; Wesemael, F. +1 more
Optical and high-dispersion IUE observations of three hot B subdwarfs (UV 1758 + 36, Ton S-227, and Feige 65) are presented. These data are analyzed with model atmosphere techniques, and element abundances for C, N, and Si are derived. The abundances are either near (N) or below (C, Si) the solar value; large variations (1) in the extent of undera…