Through the X-ray looking glass, and what plasma physics found there

How energy is transported and dissipated is the most fundamental process in the thermalization and evolution of galaxy clusters. At temperatures of 1--10 keV, intracluster medium (ICM) approximates a highly ionized plasma. Contemporary X-ray observations have revealed a wealth of substructures in the ICM, even in relatively relaxed clusters. Of particular interest is the ubiquitous presence of cold fronts, resulting from the shear interface between gaseous regions of different entropies. This configuration inevitably leads to the Kelvin-Helmholtz Instability (KHI), appearing as``horn''or``roll''features in X-ray images. Both viscosity and ordered magnetic field can suppress the growth of KHI. We present results of Chandra, XMM-Newton, and Suzaku observations of Fornax and Virgo. We probe the cluster plasma physics through the gas properties of the sloshing cold fronts, merging cold fronts, AGN bubbles, and …