Cosmic magnetism and cosmic ray propagation in the large scale universe

Abstract

This is a scholarship renewal solicitation to conclude the fifth year of the student's Ph.D. thesis who has a FAPESP scholarship (2019/04992-4) linked to the Thematic Project (2013/10559-5) coordinated by her advisor, which will be concluded in the coming July 31, 2023. During the first four years, most of the research of the initial Proposal has been carried out on studies of the origin of cosmic magnetic fields in the turbulent and weakly collisional diffuse intergalactic and intracluster of galaxies medium (IGM and ICM, respectively), through turbulent dynamo action. In order to accomplish this task, three-dimensional magnetohydrodynamic (3DMHD) simulations of a weakly collisional turbulent environment using a modified version of the PLUTO code (Mignone et al. 2007) have been performed, including all the important effects arising from low-collisionality of the medium, such as non-isotropic pressure and viscosity, and kinetic instabilities. It has also introduced a new approach employing a self-consistent time evolution of the viscous coefficients including compressive terms. An efficient dynamo amplification of seed magnetic fields has been obtained, which provides a more accurate description of the origin and maintenance of cosmic fields in diffuse media. The following step of this study is to employ for the first time this more realistic environment as the background to investigate the propagation of high energy cosmic rays (CRs) in a weakly collisional ICM and IGM, in order to evaluate the impact of the plasma effects above on their diffusion and their non-thermal radiative losses, especially at gamma-rays. For this aim, the MHD simulations above will be combined with Monte Carlo simulations of CR propagation, extending upon recent studies of our group (Santos-Lima et al. 2014; 2017; Hussain, Alves Batista, de Gouveia Dal Pino & Dolag 2021, 2023). Furthermore, considering the group's participation in the Cherenkov Telescope Array (CTA) Project and the construction of the CTA Precursor, the ASTRI MINI-ARRAY, this project is also aimed at direct applications of these studies to an appropriate description and interpretation of the observed gamma-ray emission in these environments produced by CR deflections in the propagation through IGM magnetic fields. In particular, these studies may allow the establishment of particle emission and space distribution constraints for CTA and Mini-Array cluster targets. (AU)