2024-09-27 Abstract
Title: Probing the extremes with clusters of galaxies
Speaker: Chris Reynolds (U Maryland)
Date: September 27 at 14:30
Location: R124, Physics Building
Abstract:
Clusters of galaxies provide a wonderful laboratory for studying extreme physics and astrophysics. In this talk, I will conduct a whirlwind tour of some of these investigations, both theoretical and observational. Firstly, I will show that the cores of relaxed galaxy clusters are one of the best environments to study facets of active galactic nucleus (AGN) feedback. Examining the physics at play in these feedback processes necessitates a hard look at the plasma physics of the hot intracluster medium that permeates the cluster, leading us to new understandings of processes as basic as thermal conduction. Secondly, the galaxies at the centers of relaxed clusters, and the supermassive black holes that they host, are amongst the most massive in the Universe. I will discuss these unusual central cluster AGN and present X-ray based spin measurements of the black hole in one remarkable cluster, CL1821+643, which sheds light on the growth mode of the most massive supermassive black holes. Thirdly, I will discuss the use of galaxy clusters for fundamental physics and, in particular, the extraordinary constraints that they set on certain extensions of the standard model of particle physics (namely axion-like particles). I will end with a brief discussion of the future prospects of these studies with next generation X-ray telescopes, especially the proposed Advanced X-ray Imaging Satellite (AXIS).