Reprocessing of Soft X-ray Emission Lines in Black Hole Accretion Disks
  By means of a Monte Carlo code that accounts for Compton scattering and photoabsorption followed by recombination, we have investigated the radiation transfer of Ly alpha, He alpha, and recombination continua photons of H- and He-like C, N, O, and Ne produced in the photoionized atmosphere of a relativistic black hole accretion disk. We find that photoelectric opacity causes significant attenuation of photons with energies above the O VIII K-edge; that the conversion efficiencies of these photons into lower-energy lines and recombination continua are high; and that accounting for this reprocessing significantly (by factors of 21% to 105%) increases the flux of the Ly alpha and He alpha emission lines of H- and He-like C and O escaping the disk atmosphere. 
Christopher W. Mauche, Duane A. Liedahl, Benjamin F. Mathiesen   (Lawrence Livermore Nat'l Lab.), Mario A. Jimenez-Garate (M...