Neutrinos from active black holes, sources of ultra high energy cosmic rays

A correlation between the highest energy cosmic rays (above ∼60 EeV) and the distribution of active galactic nuclei (AGN) gives rise to a prediction of neutrino production in the same sources. In this paper, we present a detailed AGN model, predicting neutrino production near the foot of the jet, where the photon fields from the disk and synchrotron radiation from the jet itself create high optical depths for proton–photon interactions. The protons escape from later shocks where the emission region is optically thin for proton–photon interactions. Consequently, cosmic rays are predicted to come from FR-I galaxies, independent of the orientation of the source. Neutrinos, on the other hand, are only observable from sources directing their jet towards Earth, i.e. flat spectrum radio sources and in particular BL Lac type objects, due to the strongly boosted neutrino emission.