2011/06/03 by G. Brunetti
Physics and Astronomy · #Acceleration #Astronomy and Astrophysical Research #Astrophysics and Cosmic Phenomena #Cluster (spacecraft) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Halo #Particle acceleration #Radio halo #Turbulence #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.1007/s12036-011-9103-7
10 pages, 2 figures, Invited talk at the conference "Diffuse Relativistic Plasmas", Bangalore, March 2011. J. Astrophys. Astr. in press
arxiv created 2011/06/03 · openalex publication_date 2011/12/01 · arxiv updated 2015/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Giant radio halos in galaxy clusters probe mechanisms of particle acceleration connected with cluster merger events. Shocks and turbulence are driven in the inter-galactic-medium (IGM) during clusters mergers and may have a deep impact on the non-thermal properties of galaxy clusters. Models of turbulent (re)acceleration of relativistic particles allow good correspondence with present observations, from radio halos to gamma-ray upper limits, although several aspects of this complex scenario remain still poorly understood. After providing basic motivations for turbulent acceleration in galaxy clusters, we discuss relevant aspects of the physics of particle acceleration by MHD turbulence and the expected broad--band non-thermal emission from galaxy clusters. We discuss (in brief) the most important results of turbulent (re)acceleration models, the open problems, and the possibilities to test models with future observations. In this respect, further constraints on the origin of giant nearby radio halos can also be obtained by combining their (spectral and morphological) properties with the constraints from gamma-ray observations of their parent clusters.