HIGH-ENERGY NEUTRINOS FROM ACTIVE GALACTIC NUCLEI

The neutrino production in AGN is reviewed with the emphasis on the diffuse neutrino flux. Most attention is given to the AGN models with the shock acceleration. The maximum energy of accelerated protons and thus of neutrinos is analysed. The maximum energy is shown to increase with the mass of black hole M and to decrease as neutrino luminosity L(nu) increases. Neutrinos with the highest energies in the diffuse spectrum are produced by the present-day sources with small L(nu) and large M, while the low-energy part of the spectrum is produced by evolving sources (with large L(nu)) at large redshifts. The analysis presented here suggests that maximum neutrino energy in the diffuse spectrum is limited by 10(5) - 10(6) GeV and therefore the detectable diffuse flux looks like a (significant) bump over atmospheric neutrino spectrum.