High-energy neutrinos from AGN?

With the advent of multi-messenger observatories, neutrino astronomy is turning into a helpful tool to investigate and put limits on the contribution of the known astrophysical objects to the diffuse neutrino background. Active Galactic Nuclei (AGN) have long been suggested among the candidate sources of cosmic high-energy neutrinos. If hadronic processes operate in the AGN jets, a lot can be learnt by combining neutrino observations with the putative accompanying electromagnetic information. This is motivated by the fact that both radiations may be pictured in the same astrophysical particle-cascades scenario, cascades that are ultimately originated by cosmic rays. While to date no neutrino point sources have been identified at high confidence, a promising ground for discovery could be the search for transient and variable neutrino/electromagnetic sources, in which case the atmospheric neutrino and muon backgrounds can be reduced by taking advantage of time- and space-coincidence. Recent outcomes in this field will be presented.