Constraining Gas Motions in the Intra-Cluster Medium
By Aurora Simionescu
The detailed velocity structure of the diffuse X-ray emitting gas that fills the space between galaxies in the densest regions of the Universe remains one of the last missing key ingredients in constraining our models of the growth and evolution of structure on the largest scales. This article summarises the various overlapping physical processes that drive the dynamics of the hot plasma in clusters of galaxies, as well as the existing, mostly indirect, measurements of the velocities of the hot plasma in clusters of galaxies. We also discuss how future high-resolution X-ray spectroscopy missions like XRISM and Athena can help us to make enormous progress in this field.