The EXOSAT obseravtions of SS Cygni.

Abstract

A series of nine observations of SS Cygni made using Exosat between 1983 November and 1984 September are presented. Distinct soft amd hard X-ray emitting components were spectrally resolved by the LE and ME instruments, respectively. In quiescence the source shows hard X-ray emission with a 2-10 keV luminosity of 1.2 x 10 exp 33 (d/200 pc)-squared erg/s. The hard X-ray emission is suppressed in outburst but shows no significant increase in photoelectric absorption. The soft X-ray emission approximately follows the optical behavior, but the outburst is delayed by 0.5-1.1 d from the optical. The rise and decay times of outburst are shorter in the soft X-ray band with respect to the optical. During outburst, the soft X-ray component is strongly modulated at a period which varies (in these observations) between 10.4 and 7.4 s.