Generalized Shock Solutions for Hydrodynamic Black Hole Accretion

For the first time, all available pseudo-Schwarzschild potentials are exhaustively used to investigate the possibility of shock formation in hydrodynamic, invicid, black hole accretion discs. It is shown that a significant region of parameter space spanned by important accretion parameters allows shock formation for flow in all potentials used in this work. This leads to the conclusion that the standing shocks are essential ingredients in accretion discs around non-rotating black holes in general. Using a complete general relativistic framework, equations governing multi-transonic black hole accretion and wind are also formulated and solved in the Schwarzschild metric. Shock solutions for accretion flow in various pseudo potentials are then compared with such general relativistic solutions to identify which potential is the best approximation of Schwarzschild space-time as far as the question of shock formation in black hole accretion discs is concerned. Subject headings: accretion, accretion disks — black hole physics — hydrodynamics — shock waves Published in the The Astrophysical Journal, 2002, Volume 577, Issue 2, pp. 880-892. Present Address: Division of Astronomy, University of California at Los Angeles, Box 951562, Los Angeles, CA 90095-1562, USA; [email protected]