We study the final fate of a very massive star by performing full general relativistic ( GR ) , three-dimensional ( 3D ) simulation with three-flavor multi-energy neutrino transport .
Utilizing a 70 solar mass zero metallicity progenitor , we self-consistently follow the radiation-hydrodynamics from the onset of gravitational core-collapse until the second collapse of the proto-neutron star ( PNS ) , leading to black hole ( BH ) formation .
Our results show that the BH formation occurs at a post-bounce time of T _ { pb } \sim 300 ms for the 70 M _ { \odot } star .
This is significantly earlier than those in the literature where lower mass progenitors were employed .
At a few \sim 10 ms before BH formation , we find that the stalled bounce shock is revived by intense neutrino heating from the very hot PNS , which is aided by violent convection behind the shock .
In the context of 3D-GR core-collapse modeling with multi-energy neutrino transport , our numerical results present the first evidence to validate a fallback BH formation scenario of the 70 M _ { \odot } star .