Particle acceleration on the largest scales: radio emission in clusters of galaxies

by Annalisa Bonafede (University of Hamburg)

Friday 6 Dec 2013, 10:30 → 11:30 Europe/Stockholm

FB42

Galaxy clusters are the largest systems in our Universe, and unique laboratories to study particle acceleration and magnetic field amplification in an almost perfect plasma. Mpc-size radio sources are observed in an increasing number of galaxy clusters. They are called "radio relics" and have been interpreted since the beginning as shock acceleration sites during cluster-cluster mergers. More recently, these models have been challenged by radio, X-ray, gamma-ray observations and theoretical works. In my talk, I will show the main pro and contra of the proposed models, and I will show new radio observations recently obtained at the Very Large Array and Giant Metrewave Radio Telescope which challenge the commonly adopted scenario. I propose a new scenario which starting from these recent observational evidence would solve the main issues regarding the origin of radio relics.