Degenerate dwarfs in future hard X-ray experiments

Abstract

The hard X-ray characteristics of weak sources (dwarf novae and AM Her-like), and strong steady sources, are discussed. HEAO A2 light curves for the greater than 2 keV flux from SS Cygni are presented, along with the pulse height spectrum and inferred incident spectrum. With regard to the high luminosity degenerate dwarf candidates, it is noted that only for Sco X-1 and Cyg X-2 has even optical evidence for binary periodicity been seen. The attributes of suitable X-ray experiments are reviewed, concerning the simultaneous observation of low energy X-rays, a large area for studying short flares, low background, and the need for both broad band spectral response and high resolution.