Brian O'Shea (Michigan State University) - Exascale simulations of supermassive black hole feedback in galaxy clusters

Galaxy clusters are the most massive virialized objects in the universe, with masses hundreds to thousands of times that of our own Milky Way and physical scales extending for megaparsecs. The bulk of the baryons contained within these systems is comprised of a hot, diffuse, and magnetized plasma that glows brightly in X-ray wavelengths. The energy radiated away by X-rays is replaced by heating from active galactic nuclei, which are relativistic jets powered by accretion onto the supermassive black hole in the cluster's central galaxy, maintaining the system in a dynamic equilibrium. This heating occurs through interactions of the AGN jet with the intracluster medium, which ultimately is transported throughout the highly X-ray luminous cluster core. In this seminar I will present results from the XMAGNET exascale magnetohydrodynamics simulations of idealized galaxy clusters with a cold gas accretion-fed, magnetized AGN jet in the center (see https://xmagnet-simulations.github.io/). I will explain the mechanisms by which cold gas triggers the AGN jet, and how the heating from this jet regulates the amount of cold gas in the system. I will also discuss in detail the generation of turbulence by the magnetized jet, the amplification of the ambient cluster magnetic fields by turbulence-driven dynamos, and the formation of multiphase gas (which is created via thermal instability) and its relationship with the cluster magnetic fields.

The Astronomy Colloquium covers a wide range of topics and should be accessible to advanced Astronomy Majors. Refreshments will be served from 3:45pm with the presentation beginning at 4:00 pm.