Galaxy-Cluster Baryons and the Cooling-Flow Problem

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AST-0507399ChandranHeating of intra-cluster plasma holds the key to some of the central problems in the study of galaxy-cluster baryons, notably the 'cooling flow problem' and problems of cluster formation, and two of the most important heat sources are central active galactic nuclei (AGN) and thermal conduction. This project will carry out high-resolution two-fluid simulations of AGN-heated cluster cores, including correct treatment of cosmic-ray pressure and buoyancy, turbulent mixing, and thermal conduction, as well as test-particle simulations of electron diffusion in turbulent magnetic fields, to improve previous approximate theories of thermal conduction. The investigation will rigorously test whether AGN heating solves the cooling flow problem, and will also show how to modify cluster-formation simulations to account for these two important heating mechanisms. This will lead to a better understanding of the relation between cluster masses and observables, and assist cluster surveys to constrain cosmological parameters.The project includes junior researcher training, but also a major outreach effort through the University's Upward Bound Project, which targets low-income and first-generation students.