Publication date: Oct 1998
Abstract:
A restricted repulsive barrier exists for equatorial photon motion in
some Kerr-Newman-de Sitter black-hole spacetimes, due to an interplay
between the rotation of the source and the cosmological repulsion. Quite
surprisingly, photons with high positive and all negative values of
their impact parameter can travel freely between the black-hole horizon
and the cosmological horizon in these spacetimes. The special class of
the Kerr-Newman-de Sitter spacetimes with restricted repulsive barriers
is represented in the space of the parameters of the geometry. The area
of the parameter space corresponding to this class is largest in the
case of Kerr-de Sitter spacetimes. With the charge parameter of the
spacetime growing, the area shrinks. In all of these cases, the mass
parameter of the spacetime must be so high that the sizes of the
black-hole and cosmological horizons are comparable.
Authors:
Stuchlík, Z.; Bao, G.; Østgaard, E.; Hledík, S.;