Search Publications
The X-Ray Spectral Properties of Accretion Disks in X-Ray Binaries
Stella, L.; Parmar, A. N.; White, N. E.
Using EXOSAT observations, the spectral properties of the persistent emission from a number of X-ray burst sources, high-luminosity low-mass X-ray binaries (LMXRB), and galactic black hole candidates are compared with various models for X-ray emission from an accretion disk surrounding a compact object in a binary system. These models include the …
EXOSAT X-ray observations of the eclipsing magnetic cataclysmic variable EX Hya.
Mason, K. O.; Cordova, F. A.; Rosen, S. R.
Mechanisms for generating the 67-min rotational X-ray modulation in EX Hya are exmined. It is concluded that the dominant process is probably absorption in material accreting onto the polar regions of the white dwarf which is symmetrically distributed about the rotation axis due to the angular offset of the dipole field. The X-ray emitting region …
A survey of the galactic plane with EXOSAT.
Warwick, R. S.; Watson, M. G.; Turner, M. J. L. +2 more
The distribution of 2 - 6 keV X-ray emission in the galactic plane in the first and fourth galactic quadrants has been measured in a series of scanning observations with the medium-energy proportional counters on EXOSAT. The results are presented as contour maps and in the form of a catalogue of 70 discrete sources.
Rotational modulation and flares on RS CVn and BY DRA systems. VII. simultaneous X-ray, radio and optical data for the dMe star YZ CMi on 4/5 March 1985.
Doyle, J. G.; Butler, C. J.; van den Oord, G. H. J. +1 more
Broad-band photometric observations of YZ CMi show a 1.2mag U-band flare at 19:55 UT on 4 March 1985, however, simultaneous X-ray observations from EXOSAT show no detectable increase. Two possible explanations for the lack of an X-ray flare may be i) a flare occurring low in the chromosphere, where the chromosphere may not have been coupled to the…
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…
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…
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…