Appearance of the central singularity in spherical collapse

Abstract

We analyze here the structure of nonradial nonspacelike geodesics terminating in the past at a naked singularity formed as the end state of inhomogeneous dust collapse. The spectrum of outgoing nonspacelike geodesics is examined analytically. The local and global visibility of the singularity is also examined by integrating numerically the null geodesics equations. The possible implications of the existence of such families for the appearance of a star in the late stages of gravitational collapse are considered. It is seen that the outgoing nonradial geodesics give an appearance to the naked central singularity like that of an expanding ball whose radius reaches a maximum before the star goes within its apparent horizon. The radiated energy (along the null geodesics), however, is shown to decay very sharply in the neighborhood of the singularity. Thus the total energy escaping via nonradial null geodesics from the naked central singularity vanishes in the scenario considered here.