Propagation of ultrahigh energy nuclei in clusters of galaxies: resulting composition and secondary emissions

TL;DR

This paper investigates how ultrahigh energy nuclei propagate in galaxy clusters, examining their survival, secondary neutrino and photon emissions, and potential detectability with current instruments.

Contribution

It provides a comprehensive numerical analysis of ultrahigh energy nuclei propagation in galaxy clusters, considering magnetic, baryonic, and photonic backgrounds, and explores implications for cosmic ray and neutrino observations.

Findings

Heavy nuclei survival depends on injection position and magnetic field profile.

Potential detection of a neutrino afterglow due to limited source lifetime.

Diffuse 1 PeV neutrino flux from clusters may be detectable by current instruments.

Abstract

We study the survival of ultrahigh energy nuclei injected in clusters of galaxies, as well as their secondary neutrino and photon emissions, using a complete numerical propagation method and a realistic modeling of the magnetic, baryonic and photonic backgrounds. It is found that the survival of heavy nuclei highly depends on the injection position and on the profile of the magnetic field. Taking into account the limited lifetime of the central source could also lead in some cases to the detection of a cosmic ray afterglow, temporally decorrelated from neutrino and gamma ray emissions. We calculate that the diffusive neutrino flux around 1 PeV coming from clusters of galaxies may have a chance to be detected by current instruments. The observation of single sources in neutrinos and in gamma rays produced by ultrahigh energy cosmic rays will be more difficult. Signals coming from lower energy cosmic rays (E < 1 PeV), if they exist, might however be detected by Fermi, for reasonable sets of parameters.