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

by C. Ferrari, H. T. Intema, E. Orrù, F. Govoni, M. Murgia, B. Mason, H. Bourdin, K. M. Asad, P. Mazzotta, M. W. Wise, T. Mroczkowski, and J. H. Croston, A&A 534, L12

alt

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.