Gravitational collapse and the cosmic antineutrino background

During their collapse to neutron stars or black holes, stellar cores emit an intense flux of electron antineutrinos produced primarily by positron capture and pair annihilation. Providing that the typical energy of these neutrinos exceeds ≡10 MeV, it has been suggested that the composite signal of all gravitational collapses that have ever occurred might be visible to detectors currently contemplated for the study of proton decay. Estimates of the antineutrino flux and spectra from Type II supernovae and the gravitational collapse of still more massive stars to black holes are obtained from numerical and semianalytic calculations of models in the mass range 10 - 5x105Mₛun;. The determined fluxes and spectra probably lie outside the range of detectability, at least in the near future.