Matter effects on neutrino oscillations in gravitational and magnetic fields - art. no. 103001

When neutrinos propagate in a background, their gravitational couplings are modified by their weak interactions with the particles in the background. In a medium that contains electrons but no muons or taons, the matter-induc ed gravitational couplings of neutrinos are different for the various neutr ino flavors, and they must be taken into account in describing the phenomen a associated with neutrino oscillations in the presence of strong gravitati onal fields. Here we incorporate those couplings in that description, inclu ding also the effects of a magnetic field, and consider the implications th at they have for the emission of high-energy neutrinos in the vicinity of a ctive galactic nuclei.