Symmetries of the asymptotically de Sitter spacetimes

Abstract

Abstract We start a systematic investigation of possible isometries of the asymptotically de Sitter solutions to Einstein equations. We reformulate the Killing equation as conformal equations for the initial data at I + . This allows for partial classification of possible symmetry algebras. In particular, if they are not maximal, they may be at most four-dimensional. We provide several examples. As a simple corollary it is shown that the only spacetime in which the Killing horizon intersects I + (after a conformal completion) is locally the de Sitter Universe.