Hydrodynamics near the central engine

Abstract

The “central engine” of quasars and active galactic nuclei is most likely powered by accretion into a supermassive black hole. A menagerie of steady state accretion flows have been developed, and these are briefly reviewed. Several examples from recent numerical calculations of axisymmetric accretion flows provide disk formation scenarios from which one can calculate plasma densities, and other values of interest for a range of accretion rates and black hole masses, These results can be compared with the well studied, but physically unrealistic case of radial accretion. Although a reasonable conceptual picture of the central engine has been developed, considerable work remains to be done.