Studies of the structure and evolution of the intracluster medium

The intracluster medium (ICM) in galaxy clusters is influenced by multiple processes, such as mergers and radiative cooling. In this dissertation we examine how these processes affect the structure and formation history of the ICM via both detailed individual cluster study and by study of bulk properties in large cluster data sets. This work provides important constraints on the evolution of the ICM, and in particular on the effects of mergers and cool core formation on ICM structure.;We use high-resolution X-ray data to identify merger features in the cluster A2319, and propose a dynamical model for the merger. Remarkably, the bulk properties of this merging cluster are not significantly perturbed relative to the values predicted by scaling relations.;This question of merger effects on bulk properties is pursued further in a study of 45 nearby clusters. We show that cool core-related phenomena, and not mergers, are the primary source of scatter in scaling relations among bulk properties. This surprising result, with greater scatter in the cool core population than in non-cool core clusters, may support cluster formation scenarios in which the presence of a cool core is primarily determined by factors beyond simply the time since the last major merger. We show that the central X-ray surface brightness can be used to significantly decrease the scatter in sealing relations by acting as a proxy for cool core "strength", a finding beneficial for duster cosmology surveys that use X-ray luminosity as a proxy for mass.;Finally, we examine how scaling relations evolve with redshift using a 70 cluster sample over the redshift range 0.18 < z < 1.24. We show that X-ray luminosity and ICM mass evolve more slowly toward higher redshifts than is predicted by self-similar models of cluster formation. Effects of core structure are again apparent in this work, as scaling relations constructed from core subtracted quantities evolve differently from those using non-core subtracted quantities, and the scatter in scaling relations and in central surface brightness increases at low redshift.