NEW G1 AND G2 INHOMOGENEOUS COSMOLOGICAL MODELS FROM THE GENERALIZED KERR-SCHILD TRANSFORMATION

New perfect-fluid solutions of Einstein's field equations have been found by means of the generalized Kerr-Schild transformation for perfect-fluid metrics. All these solutions are Petrov type D with the velocity vector of the fluid out of the two-space spanned by the two null principal directions of the Weyl tensor. In general, the solutions have just one Killing vector, but some special cases admit two commuting Killing vectors. All the solutions can be interpreted as inhomogeneous cosmological models, and an interesting property is that they contain some Friedman-Robertson-Walker metrics as special cases. Thus, they can be seen as inhomogeneous generalizations of the standard FRW cosmologies.