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The MG II emission in W UMa-type binaries.
Rucinski, S. M.
Low-resolution IUE spectra of the Mg II emission line in eight contact binaries are presented. They are discussed together with the available observations in both resolution modes for other binaries, 15 systems altogether. The relative flux R(Mg II) = f(Mg II)/f(bol), which is known to be independent of the orbital phase, is used as a measure of c…
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…
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…
Optical spectroscopy and photometry of the periodic X-ray transient AO 538-66 ( X 0535-668) during an outburst and an OFF state.
Parmar, A. N.; Branduardi-Raymont, G.; Mason, K. O. +2 more
Optical spectroscopy and photometry of the periodic X-ray transient A0538 - 66 are presented. Extensive spectroscopy performed in March 1982 follows the evolution of the multi-component line profiles through an outburst. Particularly distinctive are the broad, asymmetric emission lines which are interpreted as arising in an extensive stellar wind.…
Serendipitous EXOSAT sources in the region of the Coma cluster : active galactic nuclei with steep X-ray spectra.
Branduardi-Raymont, G.; Mason, K. O.; Martin, C. +1 more
A ≡7-hr observation of the central part of the Coma cluster of galaxies has been performed with the EXOSAT LE telescopes and CMA detectors. Five serendipitous sources are detected within the inner 35 arcmin radius of the field. Optical spectroscopy shows that four of these are background AGN not associated with the cluster. At the sensitivity leve…
Dwarf novae in outburst : simultaneous ultraviolet and optical observations of RU Pegasi and TZ Persei.
Verbunt, F.; Schwarzenberg-Czerny, A.; Jones, D. H. P. +6 more
The authors present ultraviolet and optical observations of the dwarf novae RU Peg and TZ Per during decline from outburst. In both systems the flux drops simultaneously at all wavelengths. In TZ Per the flux distributions during standstill and during the decline from different outbursts are similar. The authors discuss briefly the implications of…
IUE observations of RCB stars during extinction minima.
Evans, A.; Whittet, D. C. B.; Bode, M. F. +2 more
The R Coronae Borealis stars RY Sgr and MV Sgr have been observed with the long-wavelength (LWR) camera on the IUE satellite during deep extinction minima. The ultraviolet spectrum of RY Sgr showed a rich chromospheric spectrum, similar to that observed in the optical spectrum of this object during previous extinction episodes. Near-simultaneous o…
The ultraviolet variability of the BL Lacertae object OJ 287.
Coe, M. J.; Hanson, C. G.
The International Ultraviolet Explorer (IUE) satellite has been used to observe the BL Lacertae object, OJ287, at 26 epochs between 1978 May and 1984 May. These observations how large and often rapid variations in both the intensity and the spectral slope of the UV continuum. In general, the changes in intensity show little or no correlation with …
Upper limits to coronal line emission from X-ray detected T Tauri stars.
Penston, M. V.; Johnstone, R. M.; Lago, M. T. V. T.
High dispersion AAT spectrograms of the two T Tauri stars, GW Orionis and T Tauri, are used to set upper limits to the intensities of the coronal emission forbidden line of Fe XIV at 5303 A. Comparison made with the intensities of chromospheric and the transition-region emission lines, and of the X-ray flux, shows that in GW Ori the Fe XIV forbidd…
UV and optical observations of PG 1351+64, a bright Seyfert galaxy ORA low-luminosity QSO.
Tanzi, E. G.; Falomo, R.; Treves, A. +3 more
PG 1351+64 was repeatedly observed in 1979 - 83 with IUE. Variations of a factor of 2 in both line and continuum intensity were observed with a time-scale of ≡1 month. Coordinated optical observations suggest that the ultraviolet variability is not accompanied by optical variability, so that the overall energy distribution changes shape. The prope…