Gravitational collapse of rotating supermassive stars including nuclear burning effects

Supermassive stars (SMSs) of mass ≳105 M⊙ are candidates for seeds of supermassive black holes found in the center of many massive galaxies. We simulate the gravitational collapse of a rigidly rotating SMS core including nuclear burning effects in axisymmetric numerical relativity. We consider SMS cores composed of primordial metallicity and of helium in this paper. We find that for our chosen initial conditions, the nuclear burning does not play an important role. After the collapse, a torus surrounding a rotating black hole is formed and a fraction of the torus material is ejected by a hydrodynamical effect. We quantitatively study the relation between the properties of these objects and rotation. We find that if a SMS core is sufficiently rapidly rotating, the rest mass of the torus and outflow are approximately 6% and 1% of the initial rest mass, respectively. The typical average velocity and the total kinetic energy of the outflow are 0.2c and 1054−56 erg where c is the speed of light. Finally, we briefly discuss the possibility for observing the outflow, ringdown gravitational waves associated with the formation of black holes, and gravitational waves from the torus.