Quantum radiation from black holes and naked singularities in spherical dust collapse - art. no. 124005

A sufficiently massive collapsing star will end its life as a spacetime sin gularity. The nature of the Hawking radiation emitted during collapse depen ds critically on whether the star's boundary conditions are such as would l ead to the eventual formation of a black hole or, alternatively, to the for mation of a naked singularity. This latter possibility is not excluded by t he singularity theorems. We discuss the nature of the Hawking radiation emi tted in each case. We justify the use of Bogoliubov transforms in the prese nce of a Cauchy horizon and show that if spacetime is assumed to terminate at the Cauchy horizon, the resulting spectrum is thermal, but with a temper ature different from the Hawking temperature.