Description
The advent of next generation neutrino detectors and dark matter direct detection experiments will, hopefully, shed light on the nature of the diffuse neutrino background at the MeV scale. Supernovae and collapsars are one well studied source of this diffuse neutrino background, but it has been suggested that the collapse of Population III (Pop III) supermassive stars (SMSs) may also meaningfully contribute to the neutrino background. We calculate the neutrino signal from Pop III SMS collapse using a neutrino transfer code originally developed for core collapse supernovae and massive star collapse. The SMSs we consider are in a mass range (~10^4 Msun) thought to undergo neutrino trapping via scattering on abundant electron positron pairs, though no previous works have investigated this phenomenon in depth. We determine the location of the low density (\rho ~ 10^8 g/cc) neutrino-sphere and calculate the neutrino light-curve. The neutrino sphere survives for one to two seconds with a roughly constant radius (r ~ 3 x 10^9 cm), with it's location determined primarily by the electron scattering and nucleon absorption reactions. All models in our study (up to 6 x 10^4 Msun) have neutrino spheres, and thus low luminosity when compared to the results of a previous analytical model. We conclude that detection of neutrinos, either as burst or background, from SMSs in this mass range is unlikely; however, the SMS neutrino background is still of interest as it may serve as a source of noise in dark matter direct detection experiments.
