Direct Evidence for AGN-Powered Turbulent Heating in the Perseus Cluster from XRISM

Radio-mode AGN feedback is one of the most plausible heating mechanisms in galaxy clusters, preventing their inner gas atmospheres from catastrophic overcooling. However, the underlying physics remains poorly understood, particularly the mechanisms by which AGN-inflated bubbles transfer their energy to the intracluster medium. In this talk, I will highlight a groundbreaking result on AGN feedback from XRISM observations of the Perseus cluster, which to date remains the only cluster target that allows us to probe a broad range of dynamical scales while simultaneously achieving sufficient spatial resolution. We have mapped the gas kinematic distribution of Perseus beyond its cool-core radius, providing direct evidence for the presence of at least two dominant gas motion drivers, with a transition occurring at a radius of ~60 kpc. These drivers are associated with AGN feedback and mergers (i.e., the cosmological environment), respectively. The inner, small-scale driver sustains a heating rate at least an order of magnitude higher than that of the outer, large-scale driver, highlighting the significant role of AGN-powered turbulence in offsetting radiative cooling losses.