Impact of Galaxy Clusters on UHECR propagation

Abstract

Galaxy clusters are the universe's largest objects in the universe kept together by gravity. Most of their baryonic content is made of a magnetized diffuse plasma. We investigate the impact of such magnetized environment on ultra-high-energy-cosmic-ray (UHECR) propagation. The intracluster medium is described according to the self-similar assumption, in which the gas density and pressure profiles are fully determined by the cluster mass and redshift. The magnetic field is scaled to the thermal components of the intracluster medium under different assumptions. We model the propagation of UHECRs in the intracluster medium using a modified version of the Monte Carlo code {\it SimProp}, where hadronic processes and diffusion in the turbulent magnetic field are implemented. We provide a universal parametrization that approximates the UHECR fluxes escaping from the environment as a function of the most relevant quantities, such as the mass of the cluster, the position of the source with respect to the center of the cluster and the nature of the accelerated particles. We show that galaxy clusters are an opaque environment especially for UHECR nuclei. The role of the most massive nearby clusters in the context of the emerging UHECR astronomy is finally discussed.

12 pages, 6 figures, resived by ApJ

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• The large-scale anisotropy and flux (de-)magnification of ultra-high-energy cosmic rays in the Galactic magnetic field
• Search for GeV gamma-ray emission from SPT-CL J2012-5649 with six years of DAMPE data
• Revisiting Propagation Delays of Ultra-High-Energy Cosmic Rays from Long-lived Sources
• On gamma rays as predictors of UHECR flux in AGNs
• Study of Galactic interactions and propagation properties of ultrahigh energy cosmic rays using the precision spectrum from the Pierre Auger Observatory
• Neutrino anisotropy as a probe of extreme astrophysical accelerators