Simulations of AGN in Galaxy Clusters

Morsony Brian J, Madison WI

Investigators

Abstract

Dr. Brian Morsony is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Wisconsin-Madison. Dr. Morsony will simulate both cluster-center active galactic nuclei (AGN) and non-central AGN to assess their relative importance as a sources of heat and turbulence for the cluster and to determine how they change the magnetic field configuration of the cluster. Dr. Morsony will also determine how a range of different cluster environments affect the AGN, with the goal of creating a general prescription for AGN feedback that can be used in cosmological simulations where AGN jets are unresolved. A feedback mechanism is necessary to prevent the runaway cooling and in-fall of gas in galaxy clusters. The primary candidate for feedback is AGN powered by accretion of cool gas, which create jet outflows that heat the cluster gas to form a self-regulating cycle of cooling, accretion, outflow and heating. Understanding how feedback operates is critical to our interpretation of observations of galaxy clusters and to understanding large-scale structure formation. The proposed research will carry out a series of three-dimensional numerical simulations of AGN outflows in galaxy clusters. The simulations will include magnetohydrodynamics, gas cooling and star formation, and a link between accretion rate and AGN luminosity. This will, for the first time, allow the complete feedback loop to be simulated self-consistently. Simulations will also allow the production of synthetic X-ray and radio observations for comparison with existing observations and to determine the capabilities needed for future observatories. Dr. Morsony will also develop educational materials using black holes and associated astrophysical objects, such as AGN, gamma-ray bursts and supernova, as a tool for teaching and outreach. Materials developed will include visualization and presentation material and active-engagement questions aimed at a high-school and introductory undergraduate level. These materials will be developed through talks to the public and high school students and by teaching an undergraduate course on the Astrophysics of Black Holes. Materials will also be distributed online and by incorporation into planetarium content.