Spin light of neutrino in gravitational fields

We develop the quasiclassical theory of a massive neutrino spin evolution in the presence of gravitational fields, and the corresponding probability of the neutrino spin oscillations in gravitational fields is derived for the first time. On this basis we also predict a new mechanism for electromagnetic radiation by a neutrino moving in the vicinity of gravitating objects (the "spin light of neutrino," SLv, in gravitational fields). It is shown that the total power of this radiation is proportional to the neutrino gamma factor to the fourth power, and the emitted photon energy, for the case of an ultra relativistic neutrino, spans up to gamma-rays. We investigate the SLv caused by both gravitational and electromagnetic fields, also accounting for effects of arbitrary moving and polarized matter, in various astrophysical environments. In particular, we discuss the SLv emitted by a neutrino moving in the vicinity of a rotating neutron star, black hole surrounded by dense matter, as well as by a neutrino propagating in the relativistic jet from a quasar.