Caught in the act AGN feedback in the era of XRISM

Galaxy clusters are fossil records of billions of years of accumulated physics driving structure formation and the evolution of the Universe. Feedback from the central active galactic nuclei and mergers are key mechanisms that influence the gas in clusters by adding energy through shocks and turbulence. This thesis explores in detail these pathways and their relative contributions.
Chandra and XMM-Newton have been ubiquitous in mapping energy injection in clusters from 1999 - present. The recently launched XRISM telescope promises to build upon further by studying gas motions as low as 50 km/s with its onboard high-resolution X-ray spectroscopy instrument. XRISM should help us answer whether turbulence can be a pathway by which AGNs and mergers efficiently deposit their energy into the gas.
Chapter 1 provides an overview of cluster physics and the scope of various generations of X-ray telescopes. Chapter 2 discusses the thermodynamic history of the cluster surrounding the well-known radio source Cygnus A. Multiple temperature ripples seen in the profiles are interpreted as AGN outbursts, and their properties are calculated. Chapter 3 discusses a galaxy group named Nest200047, where multiple generations of radio bubbles are seen. How multi-generation AGN feedback affects the shallower potential of a galaxy group is explored. Chapter 4 discusses XRISM results on the Centaurus cluster. The turbulent heating is calculated and compared with the cooling power. The cluster’s abundance distribution and its implications are then discussed. Chapter 5 introduces a technique to resolve structures like cavities better with XMM-Newton for particular clusters and groups.