Discovery of radio emission in a shock heated region detected through SZ (C. Ferrari et al.)

Vol. 534
In section 1. Letters

Discovery of the correspondence between intra-cluster radio emission and a high pressure region detected through the Sunyaev-Zel’dovich effect

The diffuse radio emission of mini-halos or relics in the intergalactic medium of galaxy clusters, raises the problem of the re-acceletation of relativistic electrons, since their radiative life-time is shorter than the crossing time of the region. Shocks have been invoked as a likely source of the reacceleration. By comparing radio, X-ray, and millimetric maps of a central minihalo, the authors point out the correspondence between a radio excess in a diffuse intracluster radio source and a hot region detected through both the Sunyaev-Zel'dovich effect and X-ray observations. This indicates that electron re-acceleration is related to shocks from MHD turbulence and/or a collision/merger with a smaller cluster.