The collapse of voids in a Roberston-Walker universe with nonzero spatial curvature

Abstract

We consider the model of a spherical void (or its precursor) with heat conducting perfect fluid in Region I with Maiti metric (1982) surrounded by a spherical shell filled with radiation (Region II) having Vaidya metric. The combination is embedded in Robertson-Walker (RW) Universe in Region III. Earlier, Mandal and Banerji (1998) took RW Universe with zero spatial curvature and showed that to an observer, a little away from the boundary in Region III, the void appears to collapse provided the arrow of time is future directed in all the regions. In this paper we show that the same result holds also for the case of non-zero spatial curvature of Region III. The rate of collapse is the fastest for k = +1, moderate for k = 0, and the slowest for k = -1.