Active Galactic Nuclei Feedback in Galaxies and Clusters of Galaxies

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Super-massive black holes located in the center of a galaxy can be fueled by the accretion of gas, producing extremely energetic phenomenon (Active Galactic Nuclei, AGN) such as luminous hot disks of accreting gas and powerful outflows of relativistic plasma and magnetic fields, called jets. It has been recently recognized that powerful AGN-driven outflows directly affect the evolution of galaxies, with the kinetic energy in the jets heating the galaxy's gas and expelling it from the central bulge regions and quenching star formation. This in turn influences galaxies' star formation histories, mediating the relationship between host galaxy and central supermassive black hole, determining the number density of the most massive galaxies, and providing a fundamental energy source which regulates the thermodynamics of the surrounding hot gaseous environment, including the intracluster medium of galaxy clusters. Thus, it is clear that AGN feedback is at the heart of the fundamental processes which shape the way our universe evolved. However, major uncertainties remain about how AGN interact with the forming and evolving host galaxies and their environments, and the detailed physics of these interactions are poorly understood. The objective of the proposed research program is to develop a detailed understanding of the physical nature of the interactions and impacts of powerful AGN on their environments. My approach is to obtain multi-wavelength observations of AGN over a comprehensive range of size scales, time scales, and environmental conditions. I will study feedback in the most massive galaxies in the universe (the Brightest Cluster Galaxies) in the cores of clusters where the intracluster medium is able to cool via radiating the thermal energy of the gas. In previous work that began with a PhD student, I studied how the central AGN in the brightest cluster galaxy is able to impart energy to the hot and warm gas as well as the cold molecular gas and is able to both resupply energy to the hot but cooling gas as well as transport and disperse the colder star forming gas. The physics of this process, however, remains poorly understood. My group will reduce and analyze newly obtained optical imaging spectroscopy and Atacama Large Millimeter Array data on brightest cluster galaxies and combine our results with those from previous Chandra and radio observations. These observations will allow us to study the kinematics of both the warm and cold (molecular) gas and will explore the physics of the AGN feedback process on scales of tens of kpc. Our analysis will make use of our group's expertise in theoretical modelling of radio source propagation, interaction of radio sources with their environments, and the effects of feedback on the intracluster medium.**