Searching for radio relics and halos. Their role in the formation and acceleration of extragalactic cosmic rays

Abstract

We search for extended regions of radio emission not associated with Active Galactic Nuclei, known as 'relics', 'halos' and 'mini halo's, in a sample of 70 Abell clusters for which we have radio, optical and X-ray data. AGN can produce particle bubbles of non-thermal emission, which can restrict cosmic rays. Hence radio relics and (mini) halos could be forming as a result of the confinement of cosmic rays by these bubbles. We are probing the role that intracluster mag- netic fields (using Faraday rotation measure and inverse compton arguments), mergers (through radio/X-ray interactions), cooling flows (X-ray data), radio jets/shocks as well as radio (mini) halos/relics play in the formation, acceleration and propagation of cosmic rays. For the current study we have selected two powerful nearby radio galaxies from our sample: Hercules A and 3C 388. We report on the work in progress and future plans.

Comments: Proceedings IAU Symposium No. 275, 2008 A.C. Editor, B.D. Editor & C.E. Editor, eds