Cosmic Rays Above the Second Knee from Clusters of Galaxies and Associated High-Energy Neutrino Emission

TL;DR

This paper explores how galaxy cluster shocks could accelerate protons to produce high-energy cosmic rays and neutrinos, with potential detection by future neutrino observatories like IceCube.

Contribution

It proposes a novel scenario where galaxy clusters significantly contribute to cosmic rays between 10^17.5 and 10^18.5 eV and predicts associated neutrino signals detectable by upcoming telescopes.

Findings

Protons from cluster shocks can account for cosmic rays in the specified energy range.

The cumulative neutrino background from these processes may be detectable by IceCube or KM3NeT.

This scenario offers a new way to probe cosmic-ray confinement in galaxy clusters.

Abstract

Accretion and merger shocks in clusters of galaxies are potential accelerators of high-energy protons, which can give rise to high-energy neutrinos through pp interactions with the intracluster gas. We discuss the possibility that protons from cluster shocks make a significant contribution to the observed cosmic rays in the energy range between the second knee around 10^17.5 eV and the ankle around 10^18.5 eV. The accompanying cumulative neutrino background above PeV may be detectable by upcoming neutrino telescopes such as IceCube or KM3NeT, providing a test of this scenario as well as a probe of cosmic-ray confinement properties in clusters.