Pedro Montero - May 15, 2015

Relativistic collapse of rotating supermassive stars with thermonuclear effects

I will present results of general relativistic simulations of collapsing supermassive
stars with and without rotation using a two-dimensional general relativistic numerical
code. These numerical simulations use an equation of state which includes effects of
gas pressure, and in a tabulated form those associated with radiation and the
electron-positron pairs. We also take into account the effect of thermonuclear energy
released by hydrogen and helium burning. We find that objects with a mass of 5x10^{5}
solar mass and an initial metallicity greater than Z_{CNO}~0.007 do explode if
non-rotating, while the threshold metallicity for an explosion is reduced to
Z_{CNO}~0.001 for objects uniformly rotating. The critical initial metallicity for a
thermonuclear explosion increases for stars with mass ~10^{6} solar mass. For those
stars that do not explode we follow the evolution beyond the phase of black hole
formation. Finally, I will briefly discuss a new method that allows to perform 3D
numerical relativity simulations using spherical polar coordinates and its application
to the investigation of the gravitational collapse of very massive and supermassive
stars.