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