Publication date: Nov 2000
Abstract:
The hydrodynamical structure of perfect fluid orbiting Schwarzschild-de
Sitter black holes is investigated for configurations with uniform
distribution of angular momentum density. It is shown that in the
black-hole backgrounds admitting the existence of stable circular
geodesics, closed equipotential surfaces with a cusp, allowing the
existence of toroidal accretion disks, can exist. Two surfaces with a
cusp exist for the angular momentum density smaller than the one
corresponding to marginally bound circular geodesics; the equipotential
surface corresponding to the marginally bound circular orbit has just
two cusps. The outer cusp is located nearby the static radius where the
gravitational attraction is compensated by the cosmological repulsion.
Therefore, due to the presence of a repulsive cosmological constant, the
outflow from thick accretion disks can be driven by the same mechanism
as the accretion onto the black hole. Moreover, properties of open
equipotential surfaces in vicinity of the axis of rotation suggest a
strong collimation effects of the repulsive cosmological constant acting
on jets produced by the accretion disks.
Authors:
Stuchlík, Z.; Slaný, P.; Hledík, S.;