Publication date: May 1991
Abstract:
We study the radial motion along null geodesics in the
Reissner-Nordström-de Sitter and Kerr-de Sitter space-times. We
analyze the properties of the effective potential and we discuss
circular orbits. We find that:
1)
the radius of circular photon orbits in the Reissner-Nordström-de
Sitter space-times does not depend on the cosmological constant. We show
also how this is related to properties of the optical reference
geometry.
2)
For a specific range of the cosmological constant, photons with high
impact parameter may travel radially between the cosmological horizon
and the black hole horizon in the equatorial plane of the Kerr-de Sitter
space-times.
Authors:
Stuchlik, Zdenek; Calvani, Massimo;