The Soft X-Ray Background

Abstract

Abstract. A survey of soft X-ray background observations in the 0.1-10 keV range is presented. In the region above 1 keV, recent results on point X-ray sources are discussed and their integrated contri bution to the diffuse background is estimated. However, the average luminosity of various classes of extragalactic X-ray sources is still not sufficiently well known to permit this estimate to be made with any certainty. A discussion is given of recent observations at energies below 1 keV where the effects of interstellar absorption are important. It is argued that although some fraction of the background radiation in the 0.1-1 keV range must be galactic in origin, there is still substantial evidence for an extragalactic component. Proposed theories for generating both the galactic and extragalactic X-ray background are briefly reviewed.