Advection-dominated accretion flows in the Kerr metric. II. Steady state global solutions

Citation
R. Popham et Cf. Gammie, Advection-dominated accretion flows in the Kerr metric. II. Steady state global solutions, ASTROPHYS J, 504(1), 1998, pp. 419-430
Citations number
30
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
504
Issue
1
Year of publication
1998
Part
1
Pages
419 - 430
Database
ISI
SICI code
0004-637X(19980901)504:1<419:AAFITK>2.0.ZU;2-V
Abstract
In a previous paper, we have written equations describing steady state, opt ically thin, advection-dominated accretion onto a Kerr black hole. In this paper, we survey the numerical solutions to these equations. We find that t he temperature and density of the gas in the inner part of the accretion ho w depend strongly on the black hole spin parameter a. The rate of angular m omentum accretion is also shown to depend on a; for a greater than an equil ibrium spin parameter a(eq), the black hole is de-spun by the accretion how . We also investigate the dependence of the how on the angular momentum tra nsport efficiency alpha, the advected fraction of the dissipated energy f, and the adiabatic index gamma. We find solutions for -1 < a < 1, 10(-4) les s than or equal to alpha less than or equal to 0.44, 0.01 less than or equa l to f less than or equal to 1, and 4/3 < gamma < 5/3. For low values of al pha and f, the inner part of the flow exhibits a pressure maximum and appea rs similar to equilibrium thick disk solutions.