Electromagnetic emission from a black-to-white hole transition -- Photospheric emission

We calculate the gamma ray emission from a black-to-white hole transition. We put forward a model for the prompt emission phase, based on the photospheric emission model with the underlying idea that the number of photons and leptons emitted by the white hole will be larger than the baryon content. We calculate the spectrum of the emitted radiation and give an estimate of the total energy emitted. Finally, we estimate the cosmological density of lunar mass primordial black holes.