Testing the direct collapse scenario with general relativistic instability supernovae

The collapse of supermassive stars represents a promising avenue towards the assembly of supermassive black holes in the early universe. Observing the photospheres of these stars directly, however, may be difficult because of the large distances involved. One alternative approach is to look for observables related to violent thermonuclear explosions thought to trigger in some types of supermassive stars (general relativistic supernovae). We investigate the conditions for such an explosion by performing a general relativistic stability analysis on post Newtonian stellar evolution simulations of supermassive stars. We further examine the mechanism of the explosion with a 1D GR hydrodynamics code coupled to nuclear networks with 52, 61, 153, and 514 isotopes. Finally, we produce detailed nucleosynthetic yields and lightcurves for several types of explosions and pulsations and we conclude with a discussion of observability using current and future telescopes.