Magnetorotational Supernova Neutrino Emission Spectra and Prospects for Observations by Large-Size Underwater Telescopes

We analyze neutrino fluxes near the surface of a protoneutron star in type II supernova explosions. For magnetorotational explosion mechanism it is shown that effective neutrino collisions in a magnetized nucleon gas caused by the neutral current Gamow–Teller component lead to neutrino acceleration. Such an effect originates from spin-projection asymmetry in phase space volume of outer channel neutrino due to nucleon magnetic moment interaction with magnetic field. Respective increase in a hardness of the energy spectrum is favorable for observations of supernova neutrinos using neutrino telescopes. The possibilities of detecting supernova neutrinos by large-volume Cherenkov observatories—KM3NeT and Baikal-GVD—are discussed. As is demonstrated the upper limits of the distance thresholds for such observations can be increased by a factor of , when employing the -fold coincidence technique in data processing.