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

Published online by Cambridge University Press:  20 June 2011

Nectaria A. B. Gizani*
School of Natural Sciences and Technology, Hellenic Open University, Tsamadou 13-15 & Ag. Andreou, 26222 Patra, Greece email:
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We search for extended regions of radio emission not associated with Active Galactic Nuclei, known as ‘relics’, ‘halos’ and ‘mini halos’, 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 magnetic 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.

Copyright © International Astronomical Union 2011


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