Dr. Mathews and his team will explore the role of cosmic rays, active galactic nuclei (AGN) and dust in regulating the heating and cooling of the hot X-ray emitting gas that fills clusters of galaxies. Without a heat source, the gas at the center of large galaxy clusters is dense enough to cool and should form stars. We do not see this happening, and infer that the gas is heated in some way; this work investigates various possibilities. The team will develop detailed computational models, examining astrophysical processes including dust-aided cooling, sporadic accretion onto and energy injection from AGN, cosmic-ray acceleration/diffusion/heating, and convection. He will perform analytic studies and hydrodynamic simulations of cavities that are inflated in the X-ray-emitting gas by cosmic rays; to explore mass and energy circulation driven by active galactic nuclei; and to calculate the radiation from dust grains heated by random impacts with particles in the hot gas.
Dr. Mathews will write a popular science article on their research, and will give several public lectures at the Santa Cruz Museum of Natural History. A postdoctoral scholar will be trained by taking part in the research.
