Gravitational collapse of null fluid on the brane

We first obtain the analogue of Vaidya's solution on the brane for studying the collapse of null fluid onto a flat Minkowski cavity on the brane. Sinc e the back-reaction of the bulk onto the brane is supposed to strengthen gr avity on the brane, it would favor formation of black hole as against naked singularity. That is the parameter window in the initial data set giving r ise to naked singularity in the 4D Vaidya case would now get partially cove red. (C) 2001 Published by Elsevier Science B.V.