High-Energy Neutrino and Gamma Ray Production in Clusters of Galaxies

Abstract

We compute the contribution from clusters of galaxies to the diffuse neutrino and $\gamma -$ray background. Due to their unique magnetic-field configuration, cosmic rays (CRs) with energy $\le 10^{17}$ eV can be confined within these structures over cosmological time scales, and generate secondary particles, including neutrinos and $\gamma -$rays, through interactions with the background gas and photons. We employ three-dimensional (3D) cosmological magnetohydrodynamical (MHD) simulations of structure formation to model the turbulent intergalactic and intracluster media. We propagate CRs in these environments using multi-dimensional Monte Carlo simulations across different redshifts (from $z\sim 5$ to $z=0$), considering all relevant photohadronic, photonuclear, and hadronuclear interactions. We also include the cosmological evolution of the CR sources. We find that for CRs injected with a spectral index $1.5-2.7$ and cutoff energy $E_{\text{max}}=10^{16}-10^{17}$~eV, clusters contribute to a substantial fraction to the diffuse fluxes observed by the IceCube and Fermi-LAT, and most of the contribution comes from clusters with $M>10^{14}{M}_{\odot }$ and redshift $z<0.3$. We also estimated the multimessenger contributions from the local galaxy cluster.

8 pages 3 figures