Thick Accretion Disks and Supercritical Luminosities

Models of thick accretion disks surrounding black holes are developed which have a consistent time-averaged stationary behavior, and implications of these models for disk luminosity are examined. The approach employed uses a pseudo-Newtonian potential which reproduces many of the important features of the Schwarzschild solution and is not explicitly dependent on the assumed form of the viscosity law, with a global energy conservation requirement and a critical local radiated flux. The resulting disks have cusps at their inner edges, which lie between the marginally bound and marginally stable orbits, and depend on the specified angular momentum distribution. Accretion rates can become very large, and the total luminosity can exceed the nominal Eddington luminosity due to geometrical effects, possibly leading to the formation of well-collimated beams. In addition, the thick models derived can be matched onto relatively thin disks beyond a certain transition radius.