Diffuse neutrino flux from blazars via cosmic-ray propagation in extragalactic medium

The origin of the cosmic neutrino signal measured by IceCube is still unknown. A general correlation between the sources of high-energy gamma-ray sources with IceCube neutrinos is expected since hadronic interactions are the crucial precursors of both messengers at such high energies. Blazars dominate the extragalactic gamma-ray sky. However, neutrinos originating from inside the blazar jets cannot account for more than similar to 30% of the diffuse flux. We study ultrahigh-energy cosmic-ray contribution to the diffuse flux through photopion interactions on cosmic background photons. The extragalactic background light, consisting of IR/UV/optical photons require a proton energy threshold of E-th(p,pi) approximate to 1017 eV for pion production. The latter can yield PeV neutrinos. We analyze the total contribution from resolved and unresolved blazars by using a luminosity-dependent density evolution of blazars. The latest Fermi-LAT 4LAC catalog sheds light on the redshift distribution of the diffuse neutrino flux for resolved gamma-ray blazars.

Automated summary

This article discusses the origin of the cosmic neutrino signal measured by IceCube, pointing out the correlation between high-energy gamma-ray sources and neutrinos, and studies the contribution to the diffuse flux, with a special focus on the role of blazars.