Optically thick, time-dependent spherical accretion onto a black hole. I - Equations and numerical methods

Abstract

view Abstract Citations (21) References (44) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Optically thick, time-dependent spherical accretion onto a black hole. I - Equations and numerical methods Vitello, P. Abstract Accretion onto a compact object is almost certainly the mechanism powering many of the observed powerful X-ray sources, and may also be the key to the luminosity from the nuclei of active galaxies and QSOs. Consideration is given to the equations for fully relativistic, optically thick, spherical, time-dependent accretion onto a black hole, as well as an approach to their numerical solution. Radiation energy transport is treated in the diffusion approximation, and magnetic dissipative heating is included. An implicit algorithm with a fixed Eulerian spatial mesh is presented, allowing accurate treatment of flow for which the time scales vary rapidly with radius. Examples of accretion flows which are optically thin at large radii, and which are optically thick everywhere, are given. These flow solutions were all found to quickly converge to steady state. With no magnetic dissipation, the net escaping luminosities are much less than the Eddington luminosity. With dissipation, however, net luminosities near the Eddington luminosity can be readily achieved. Publication: The Astrophysical Journal Pub Date: September 1984 DOI: 10.1086/162419 Bibcode: 1984ApJ...284..394V Keywords: Black Holes (Astronomy); Computational Astrophysics; Galactic Nuclei; Hydrodynamic Equations; Optical Thickness; Stellar Mass Accretion; Active Galaxies; Difference Equations; Euler Equations Of Motion; Luminosity; Radiative Transfer; Relativistic Effects; Astrophysics full text sources ADS |