Energy flux through the horizon in the black hole-domain wall systems

We study various configurations in which a domain wall (or cosmic string),described by the Nambu-Goto action, is embedded in a background space-time of ablack hole in $(3+1)$ and higher dimensional models. We calculate energy fluxesthrough the black hole horizon. In the simplest case, when a static domain wallenters the horizon of a static black hole perperdicularly, the energy flux iszero. In more complicated situations, where parameters which describe thedomain wall surface are time and position dependent, the flux is non-vanishingis principle. These results are of importance in various conventionalcosmological models which accommodate the existence of domain walls and stringsand also in brane world scenarios.Comment: references added, accepted for publication in JHE