Spectral diagnostics and accretion disk corona reprocessing in x‐ray binaries

Abstract

Emission lines are valuable probes of the conditions in the accretion flows associated with binary x‐ray sources. In this review I describe examples of emission lines in different spectral bands, review the observations, and discuss what they indicate about the conditions in binary x‐ray sources. These lines are interpreted using an x‐ray illuminated accretion disk model; the structure and dynamics of the heated disk, its spectral signatures, and the major unsolved theoretical issues surrounding them are discussed.