Faraday Rotation Measure Dependence on Galaxy Clusters Dynamics

Abstract

We study the magnetic fields in galaxy clusters through Faraday rotation measurements crossing systems in different dynamical states. We confirm that magnetic fields are present in those systems and analyse the difference between relaxed and unrelaxed samples with respect to the dispersion between their inherent Faraday rotation measurements (RM). We found an increase of this RM dispersion and a higher RM overlapping frequency for unrelaxed clusters. This fact suggests that a large-scale physical process is involved in the nature of unrelaxed systems and possible depolarization effects are present in the relaxed ones. We show that dynamically unrelaxed systems can enhance magnetic fields to large coherence lengths. In contrast, the results for relaxed systems suggests that a small-scale dynamo can be a dominant mechanism for sustaining magnetic fields, leading to intrinsic depolarization.