Turbulence and magnetic fields in clusters of galaxies

Abstract

Magnetic fields in clusters of galaxies play a critical role in shaping up the intracluster medium. Their existence has been established through the rotation measure of polarized radio galaxies and the synchrotron emission of cluster-wide diffuse sources. In the so-called Sausage relic, which is one of giant radio relics detected in a cluster outskirt, for instance, the magnetic fields are believed to have a few microG strength and a Mpc scale. The observed magnetic fields are conjectured to be produced by the process of small-scale turbulence dynamo due to turbulence in the intracluster medium (ICM). To investigate the dynamo origin, we simulate the development of turbulence and the follow-up amplification of magnetic fields in galaxy clusters using a three-dimensional MHD code. Turbulence is induced in highly stratified backgrounds expected in clusters and driven sporadically mimicking major mergers. We here present the results, aiming to answer whether the turbulence dynamo scenario can explain the observed magnetic fields in clusters of galaxies.