Revealing the Kinematics of Hot Plasma in Galaxy Clusters: First Results from XRISM

The recent launch of the XRISM observatory has opened a new era in high-energy astrophysics, delivering long-anticipated high-resolution spectra of extended X-ray sources, including galaxy clusters. These systems are filled with hot plasma that occupies the space between galaxies. For the first time, XRISM provides direct kinematic measurements of this intracluster plasma across many clusters, offering new insight into the circulation of energy driven by supermassive black hole feedback and cluster mergers - two key processes shaping the evolution of massive galaxies and galaxy clusters. In this talk, I will highlight selected XRISM results from observations of several well-known, bright clusters. I will discuss gas kinematics near central supermassive black holes and the presence of multiple velocity cascades, the “stormy weather’’ of the Coma cluster and its unusual velocity power spectrum, and new kinematic measurements in the outskirts of clusters, at radii most relevant for cluster cosmology.