GREG BRYAN, COLUMBIA UNIVERSITY

PRINCETON ASTRONOMY COLLOQUIUM - FEBRUARY 8, 2005

ABSTRACT

Cooking With (Cluster) Gas: Understanding the Formation and Evolution of Galaxy Clusters

The new X-ray observatories have unleashed an explosion of data about the hot gas in galaxy clusters, in the process overturning cherished theories and posing new puzzles, particularly about the impact of AGN on the thermal state of the cluster gas. I review what can be understood from observations, simple theory and high-resolution numerical simulations, showing show that in some areas -- such as the temperature profile at large radii -- the latest observational results are in surprisingly good agreement with theory. On the other hand, the impact of cooling and heating on the core, and on global scaling relations are still not well understood. I use new simulations to argue that there are, in fact, two separate heating/cooling issues in galaxy clusters and the resolution of these issues may tell us something very important about high-redshift galaxy formation.