High-Energy Spectra from Black-Hole Candidates

Abstract

Our knowledge of the high-energy emission spectra from black-hole candidates has increased enormously with missions like BeppoSAX and RossiXTE, thanks to their broad-band window. I present the main and most solid points of this current knowledge, both in terms of detailed spectral modeling of X-ray broad-band spectra, and more generally in relation to the "black-hole state paradigm", which links spectral and timing properties of accretion disks. Finally, through the discussion of recent results on two systems, XTE J1650-500 and GX 339-4, I present evidence for a new view of the state paradigm.