Constraining Gas Motions in the Intra-Cluster Medium

摘要: The detailed velocity structure of the diffuse X-ray emitting intra-cluster medium (ICM) remains one last missing key ingredients in understanding microphysical properties these hot baryons and constraining our models growth evolution on largest scales Universe. Direct measurements gas velocities from widths shifts emission lines were recently provided for central region Perseus Cluster galaxies by Hitomi, upcoming high-resolution microcalorimeters onboard XRISM Athena are expected to extend studies many more systems. In mean time, several other direct indirect methods have been proposed estimating ICM, ranging resonant scattering surface brightness fluctuation analysis, kinematic Sunyaev-Zeldovich effect, or using optical line nebulae brightest cluster as tracers motions ambient plasma. Here, we review compare existing estimates baryons, well various overlapping physical processes that drive discuss implications viscosity identifying source turbulence clusters galaxies.