Black holes and dark energy from gravitational collapse on the brane

Abstract

The gravitational collapse of a pressureless fluid in general relativity (Oppenheimer–Snydercollapse) results in a black hole. The study of the same phenomenon in the brane-worldscenario has shown that the exterior of the collapsing dust sphere cannot be static. Weshow that by allowing for pressure, the exterior of a fluid sphere can be static. Thegravitational collapse on the brane proceeds according to the modified gravitationaldynamics, turning the initial nearly dust-like configuration into a fluid with tension. Thetension arises from the nonlinearity of the dynamical equations in the energy–momentumtensor, and it vanishes in the general relativistic limit. Below the horizon the tension turnsthe star into dark energy. This transition occurs right below the horizon for astrophysicalblack holes and far beyond the horizon for intermediate mass and galactic black holes.Further, both the energy density and the tension increase towards infinite values during thecollapse. The infinite tension, however, could not stop the formation of the singularity.