Naval Research Laboratory
Relativistic electrons in the sloshing cores of galaxy clusters: observations of radio minihalos
Radio minihalos are rare diffuse synchrotron sources found in the cool cores of a number of galaxy clusters. Their existence requires magnetic fields and ultra-relativistic electrons to be distributed throughout a large fraction of the cluster central core. It has been proposed that sloshing motions of the cool gas in the core may be responsible for the origin of minihalos. In particular, turbulence, generated by these motions, can reaccelerate seed electrons (e.g., from past activity of the central AGN) to ultra-relativistic energies and produce diffuse radio synchrotron emission that is spatially coincident with the sloshing region. In this talk, I will present striking examples of minihalos supporting the sloshing scenario. I will also present results of our recent statistical study of minihalos and their correlation with the X-ray and Sunyaev-Zel'dovich (SZ) properties of the cluster hosts.