Radiation Feedback in Hot Accretion-Disk Corona Models

We present a detailed study of the observable effects of photoionization and Comptonization of line and continuum radiation from a cold accretion disk with a thin, warm, photoionized transition layer in the framework of self-consistent accretion-disk corona models for Galactic black-hole candidates. We use an iterative method to treat the non-linear radiation feedback between the transition layer and the hot corona numerically using a Monte-Carlo Comptonization code in combination with the photoionization and line transfer code XSTAR. The subset of the parameter space allowed in self-consistent accretion-disk corona systems on energetic grounds is explored, checking for the emergence of emission lines and/or absorption edges, with special emphasis on the spectral range $E \lesssim 1$ keV where such features might become observable with the advent of the AXAF satellite. Comparing our model calculations to the broadband spectrum of GX~339-4, we find good agreement with the observed spectral features and discuss how the future detection of the predicted features at lower energies can be used to constrain parameters.