High-energy neutrinos from sources in clusters of galaxies

TL;DR

This paper investigates how galaxy clusters can accelerate and confine high-energy cosmic rays, producing neutrinos that may account for a significant portion of IceCube's observed neutrino flux without conflicting with cosmic ray and gamma-ray observations.

Contribution

It presents a realistic model of cosmic ray propagation and interaction in galaxy clusters, showing their potential to explain high-energy neutrinos detected by IceCube.

Findings

Galaxy clusters can produce neutrinos matching IceCube observations above 30 TeV.

Clusters can contribute significantly to the neutrino flux without detectable cosmic ray or gamma-ray signals.

The model aligns with observed neutrino spectra under reasonable astrophysical assumptions.

Abstract

High-energy cosmic rays can be accelerated in clusters of galaxies, by mega-parsec scale shocks induced by accretion of gas during the formation of large-scale structure, or by powerful sources harbored in clusters. Once accelerated, the highest energy particles leave the cluster via almost rectilinear trajectories, while lower energy ones can be confined by the cluster magnetic field up to cosmological time and interact with the intracluster gas. Using a realistic model of the baryon distribution and the turbulent magnetic field in clusters, we studied the propagation and hadronic interaction of high-energy protons in the intracluster medium. We report the cumulative cosmic ray and neutrino spectra generated by galaxy clusters including embedded sources, and demonstrate that clusters can contribute a significant fraction of the observed IceCube neutrinos above 30 TeV while remaining undetected in high-energy cosmic rays and $\gamma$ rays for reasonable choices of parameters and source scenarios.