Lyman Edge Features from Accretion Disks Around Maximally Rotating   Supermassive Black Hole
  We calculate the amplitude of the Lyman discontinuity for an accretion disk around a maximally rotating black hole. The locally emitted disk spectrum is computed with a previously developed numerical model (Sincell and Krolik 1998) and then a new general relativistic ray-tracing code is used to determine the observed spectra as a function of inclination angle, theta_o. We find that Lyman discontinuities are undetectable for disks viewed at inclinations cos(theta_o) < 0.8, but a significant feature remains for disks seen face-on. 
Mark W. Sincell