Failed supernova simulations beyond black hole formation

We present an axisymmetric failed supernova simulation beyond black hole formation, for the first time with numerical relativity and two-moment multi-energy neutrino transport. To ensure stable numerical evolution, we use an excision method for neutrino radiation hydrodynamics within the inner part of black hole domain. We demonstrate that our excision method is capable of stably evolving the radiation hydrodynamics in dynamical black hole space-time. As a remarkable signature of the final moment of proto-neutron star (PNS), we find the emergence of high-energy neutrinos. Those high-energy neutrinos are associated with the PNS shock surface being swallowed by the central black hole and could be a possible observable of failed supernovae.