High Energy Neutrinos from Quasars

. We review and clarify the assumptions of our basic model for neutrino production in the cores of quasars, as well as those modi(cid:12)cations to the model made subsequently by other workers. We also present a revised estimate of the neutrino background (cid:13)ux and spectrum obtained using more recent empirical studies of quasars and their evolution. We compare our results with other theoretical calculations and experimental upper limits on the AGN neutrino background (cid:13)ux. We also estimate possible neutrino (cid:13)uxes from the jets of blazars detected recently by the EGRET experiment on the Compton Gamma Ray Observatory. We discuss the theoretical implications of these estimates. EGRET observed time variability on the order of a day from 3C279, implying relativistic beaming. Let us further assume the the observed (cid:13)-rays are produced by high energy protons, leading to pion production and the subsequent decay of neutral pions into (cid:13)-rays and accompanying charged pions into electrons, positrons and neutrinos. We further note that the observed di(cid:11)erential spectrum of 3C279 is consistent with a roughly E (cid:0)2 power law up to energies in excess of 5 GeV (Hartman, et al. 1992), as would be expected for shock accelerated proton primaries leading to pion decay (cid:13)-rays. Also, the detection of (cid:13)-rays above 0.5 TeV from Mrk 421 by the Whipple Observatory group (Punch, et al. 1992), in combination with the EGRET detection, implies a roughly E (cid:0)2 spectrum for this source up to TeV energies and possibly beyond. Such high energies are hard to account for from electron acceleration alone, since radiative energy losses of electrons at such energies are quite severe.