Probing Cosmic Rays in AGN and Clusters of Galaxies using radio observations

We search for radio structures not associated with Active Galactic Nuclei (e.g.haloes, mini halos, relics) in a sample of 70 Abell clusters for which we have radio, optical and X-ray data.Radio galaxies are known sources of high energy.Most galaxy clusters have cool cores with active galaxies at their centre.These AGN contain particle bubbles that show nonthermal radio emission.We are probing the role that intracluster magnetic fields, mergers, cooling flows, radio jets/shocks as well as radio halos/relics play in the formation and acceleration of cosmic rays.Faraday rotation quantitatively establishes both cosmic ray and magnetic pressure component in the intracluster medium.Rotation measurements of background and cluster radio sources, together with X-ray observations provide the main evidence of large-scale intra-cluster magnetic fields and of densities of relativistic electrons.The intracluster medium of galaxy clusters is permeated by significant magnetic fields, which suggests that trapping and acceleration of cosmic rays by the external magnetic field could be occuring.Radio spectral observations indicate the ageing of the emitting particles.In the current paper we discuss results from the radio and X-ray analysis of two powerful radio galaxies from our sample namely Hercules A, and 3C 388.