Berezinsky Hidden Sources: An Emergent Tension in the High-Energy Neutrino Sky?

Abstract: The IceCube Collaboration has recently reported compelling evidence of high-energy neutrino emission from NGC~1068, and also mild excesses for NGC 4151 and CGCG420-015, local Seyfert galaxies. This has increased the interest along neutrino emission from hot-corona surrounding the super massive black holes of Seyfert Galaxies. In this paper, we revisit phenomenological constraints on the neutrino emission from hot-coronae of seyfert galaxies, using an assumption of equi-ripartition between cosmic-rays and magnetic energy densities. We show that not only these sources are consistent with such an assumption but also that the data point towards low beta plasma parameters inside Seyfert Galaxies. We exploit this finding to constrain the Seyfert diffuse neutrino flux and we obtain that, in order not to overproduce neutrinos, not all the sources can be in an equi-ripartition state. We conclude (along with previous findings) that seyfert galaxies cannot explain the diffuse neutrino spectrum above $\sim 100\, \rm TeV$, allowing space for other astrophysical sources.