Galaxy Cluster simulations with a spectral Cosmic Ray model -- "Wrong Way" Radio Relics

TL;DR

This paper introduces a novel spectral Cosmic Ray model integrated into galaxy cluster simulations, enabling detailed on-the-fly evolution of CR populations and providing insights into radio relic formation.

Contribution

It develops an efficient on-the-fly Fokker-Planck solver for CRs, allowing simultaneous evolution of protons and electrons in high-resolution galaxy cluster simulations.

Findings

Preliminary results suggest a new formation mechanism for 'Wrong Way' Radio Relics.

The spectral CR model captures shock acceleration, re-acceleration, and radiative processes.

Simulation results offer insights into non-thermal emissions and magnetic field structures in galaxy clusters.

Abstract

Non-thermal emission from relativistic electrons gives insight into the strength and morphology of intra-cluster magnetic fields, as well as providing powerful tracers of structure formation shocks. Emission caused by Cosmic Ray (CR) protons on the other hand still challenges current observations and is therefore testing models of proton acceleration at intra-cluster shocks. Large-scale simulations including the effects of CRs have been difficult to achieve and have been mainly reduced to simulating an overall energy budget, or tracing CR populations in post-processing of simulation output and has often been done for either protons or electrons. We use an efficient on-the-fly Fokker-Planck solver to evolve distributions of CR protons and electrons within every resolution element of our simulation. The solver accounts for CR acceleration at intra-cluster shocks, based on results of recent PIC simulations, re-acceleration due to shocks and MHD turbulence, adiabatic changes and radiative losses of electrons. We apply this model to zoom simulations of galaxy clusters, recently used to show the evolution of the small-scale turbulent dynamo on cluster scales. For these simulations we use a spectral resolution of 48 bins over 6 orders of magnitude in momentum for electrons and 12 bins over 6 orders of magnitude in momentum for protons. We present preliminary results about a possible formation mechanism for Wrong Way Radio Relics in our simulation.