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The 1985 May superoutburst of the dwarf nova OY Carinae - II. IUE andEXOSAT observations.
Sonneborn, G.; van Paradijs, J.; Charles, P. A. +4 more
The authors present ultraviolet (IUE) and X-ray (EXOSAT) observations of the eclipsing dwarf nova OY Carinae during the superoutburst of 1985 May. From the lack of X-ray eclipse and UV behaviour they deduce that the X-ray flux originates in an optically thin corona comparable in size to the Roche lobe, and not directly from the white dwarf or boun…
Measurements of the Gas Temperature and Iron Abundance Distribution in the Coma Cluster
Hughes, John P.; Gorenstein, P.; Fabricant, D.
The medium energy X-ray detectors onboard the EXOSAT Observatory have been used to determine the gas temperature at several positions in the Coma Cluster of galaxies. We find evidence at greater than 95% confidence for a higher temperature in the center of the cluster than in a position approximately 45' off-center. No difference in iron abundance…
Evidence for rotationally modulated variability in O star winds.
Prinja, Raman K.
The nature of variability observed in the UV resonance line P Cygni profiles of four O stars is interpreted in terms of recurrent episodes of low-velocity broad absorption enhancements evolving into high-velocity narrow absorption components. Profile fitting techniques are used to determine the central velocities of the (multiple) features. The re…
Variability of the soft excess in the Seyfert I galaxy MKN 335.
Turner, T. J.; Pounds, K. A.
The luminous Seyfert I galaxy Mkn 335 was observed by EXOSAT on six occasions between 1983 November 5 and 1985 December 24. A previous analysis of the 1984 December 6 observation revealed a two-component spectrum, with a hard power law dominant above ~2 keV on which was superimposed a strong soft X-ray excess in the 0.1-2 keV band of the EXOSAT lo…
IUE Observations of Z Andromedae: Spectral Variations during Quiescence and a Physical Model
Fernandez-Castro, Telmo; Cassatella, Angelo; Gimenez, Alvaro +1 more
The authors describe the results of an extensive monitoring of the ultraviolet spectrum of the symbiotic star Z And based on high- and low-resolution IUE observations made during 1978 - 1982, when the star was in a phase of quiescence. Large variations of the Balmer continuum and emission-line intensities where observed on a time scale of about 76…
4U 1626-67: The Binary with the Smallest Known Mass Function
van der Klis, M.; Verbunt, F.; Rappaport, S. +3 more
The pulsating X-ray source 4U 1626-67 is an accreting neutron star in a binary system with a very low mass companion. The authors observed the source with EXOSAT continuously for 23 hr on 1986 March 30 - 31 UT. These observations allow them to set a stringent upper limit on the projected semimajor axis of the orbit of the neutron star. The corresp…
An EXOSAT observation of an X-ray flare and quiescent emission from the RS CVn binary sigma2 CrB.
Mewe, R.; Brinkman, A. C.; van den Oord, G. H. J.
The RS CVn binary sigma2 Coronae Borealis was observed with medium-energy and low-energy detectors and the transmission grating spectrometer aboard EXOSAT, and a strong X-ray flare rising within about five minutes and lasting more than two hours was detected. The temperature rises steeply within three minutes from 19 MK to a value well above 70 MK…
The discovery of orbital dips in the soft X-ray emission of U GEM during an outburst.
King, A. R.; Watson, M. G.; Mason, K. O. +1 more
A series of Exosat and IUE observations of the dwarf nova U Geminorum have been made during the decline from an unusually long outburst that occurred in 1985 October and November. A strong soft X-ray flux was recorded which is modulated with the orbital period of the binary. The modulation takes the form of broad, deep dips whose morphology change…
X-ray observations of the 50-min dipping source XB 1916-053.
Mason, Keith O.; Smale, Alan P.; White, Nick E. +1 more
Three EXOSAT observations of the low-mass X-ray binary XB 1916-053 have revealed extreme variability in the appearance of the dips, ranging from complete absence to two broad, deep dips per 50-min cycle. These dips are believed to result from the obscuration of the central X-ray source by azimuthal structure in the accretion disc. The X-ray spectr…
Stellar coronae with EXOSAT : broad band spectroscopy of nearby coronal sources.
Schmitt, J. H. M. M.; Monsignori-Fossi, B. C.; Landini, M. +1 more
Broad-band observations of stellar coronae obtained with the Low Energy experiment on board the Exosat satellite are presented, together with a technique for the analysis of Exosat low-energy data. The limitations of filter spectroscopy with Exosat are discussed. Specific relationships are provided for extracting physical quantities (temperature, …