MATCHING OF THE VAIDYA AND ROBERTSON-WALKER METRIC

We give the necessary conditions for the matching of a general Robertson-Walker geometry to a general spherically symmetric radiating metric. We also found the conditions for the matching of a Vaidya metric to a general Robertson-Walker metric. The possible applications of the results to the stellar collapse and to the study of local inhomogeneities in a cosmological context are considered. An alternative interpretation of the energy-momentum tensor of the Robertson-Walker part of spacetime is given in such a way that the physical processes can be better understood.