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

TL;DR

This paper investigates high-energy neutrino emission from Seyfert galaxies' hot coronae, constraining their contribution to the diffuse neutrino flux and highlighting the limitations of Seyfert galaxies as sole sources above 100 TeV.

Contribution

It provides phenomenological constraints on neutrino emission from Seyfert galaxies' hot coronae, considering energy equipartition and plasma parameters, and assesses their role in the high-energy neutrino spectrum.

Findings

Seyfert galaxies are consistent with energy equipartition assumptions.

Data suggests low beta plasma parameters inside Seyfert galaxies.

Seyfert galaxies cannot fully explain the diffuse neutrino flux above 100 TeV.

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.