A Case for Radio Galaxies as the Sources of IceCube's Astrophysical Neutrino Flux

TL;DR

This paper argues that radio galaxies are the main sources of high-energy astrophysical neutrinos detected by IceCube, proposing a model where cosmic-ray interactions within these galaxies produce both neutrinos and gamma rays.

Contribution

It introduces a simple physical model linking cosmic-ray interactions in radio galaxies to observed neutrino and gamma-ray fluxes, supporting their role as primary neutrino sources.

Findings

Radio galaxies can produce neutrino fluxes matching IceCube observations.

The model accounts for both neutrino and gamma-ray diffuse fluxes.

Radio galaxies may also be sources of the highest energy cosmic rays.

Abstract

We present an argument that radio galaxies (active galaxies with mis-aligned jets) are likely to be the primary sources of the high-energy astrophysical neutrinos observed by IceCube. In particular, if the gamma-ray emission observed from radio galaxies is generated through the interactions of cosmic-ray protons with gas, these interactions can also produce a population of neutrinos with a flux and spectral shape similar to that measured by IceCube. We present a simple physical model in which high-energy cosmic rays are confined within the volumes of radio galaxies, where they interact with gas to generate the observed diffuse fluxes of neutrinos and gamma rays. In addition to simultaneously accounting for the observations of Fermi and IceCube, radio galaxies in this model also represent an attractive class of sources for the highest energy cosmic rays.