Chaplygin-like gas and branes in black hole bulks

We explore the possibility to locate a brane in black hole backgrounds. We study explicitly the cases of BHTZ and Schwarzschild-anti de Sitter (AdS) b lack holes. Our result is that branes cannot be supported by brane tension alone and it is necessary to introduce other forms of matter on the brane, We find classes of perfect fluid solutions obeying to peculiar state equati ons. For the case of BHTZ bulk geometry the state equation takes exactly th e form of a "Chaplygin gas", which is relevant in the brane context. In the Schwarzschild-AdS case we find new state equations which reduce to the Cha plygin form when the brane is located near the horizon. (C) 2000 Elsevier S cience B.V. All lights reserved.