Turbulence and Cosmic-Rays in Galaxy Clusters

Peng Oh (UCSB)

Much as in the ISM, the non-thermal component of the ICM of galaxy clusters, such as turbulence and cosmic-rays, can exert a profound influence. Turbulence: I describe the interaction between turbulence and conduction in the cores of galaxy clusters. Turbulence can overwhelm the heat buoyancy instability (HBI) to randomize magnetic field lines. The reestablishment of conduction, as well as turbulence heat transport, can stave off a cooling catastrophe. I also describe a new mixture model method of analyzing turbulence and bulk motions in high-resolution X-ray spectra. Cosmic rays: the streaming of cosmic rays can heat the ICM. Under certain conditions, streaming can become super-Alfvenic, modulating the appearance of radio halos. I also describe how relic cosmic-ray electrons from structure formation can serve as a pool for re-acceleration in producing radio relics.