On the origin and acceleration of cosmic rays: Cooling flow clusters and
  AGN hosts
  We are looking for radio `relics' and `halos' in an X-ray selected sample of
clusters of galaxies. These radio features are not a product of the Active
Galactic Nuclei (AGN)-mechanism, but more likely are associated with past
cluster merger events. AGN hosts of cooling flow clusters contain particle
bubbles that show non-thermal radio emission. These bubbles could explain the
presence of radio relics and halos if they can restrict cosmic rays
efficiently. Intracluster magnetic fields and cluster environments can reveal
the acceleration mechanisms of cosmic rays. Using radio/X-ray data and
analytical methods we examine three AGN hosts out of our 70 clusters, namely
Hercules A, 3C310 and 3C388. We found that none of these clusters contain
relics and/or halos.
