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To better constrain models of cool core galaxy cluster formation, we haveused X-ray observations taken from the Chandra and ROSAT archives to examinethe properties of cool core and non-cool core clusters, especially beyond thecluster cores. We produced X-ray images, surface brightness profiles, andhardness ratio maps of 30 nearby rich Abell clusters (17 cool cores and 13non-cool cores). We show that the use of double beta-models with cool coresurface brightness profiles and single beta-models for non-cool core profilesyield statistically significant differences in the slopes (i.e., beta values)of the outer surface brightness profiles, but similar cluster core radii, forthe two types of clusters. Hardness ratio profiles as well asspectroscopically-fit temperatures suggest that non-cool core clusters arewarmer than cool core clusters of comparable mass beyond the cluster cores. Wecompared the properties of these clusters with the results from analogouslyreduced simulations of 88 numerical clusters created by the AMR Enzo code. Thesimulated surface brightness profiles have steeper beta-model fits in the outercluster regions for both cool cores and non-cool cores, suggesting additionalICM heating is required compared to observed cluster ICMs. Temperature andsurface brightness profiles reveal that the simulated clusters are over-cooledin their cores. As in the observations, however, simulated hardness ratio andtemperature profiles indicate that non-cool core clusters are warmer than coolcore clusters of comparable mass far beyond the cluster cores. The generalsimilarities between observations and simulations support a model described inBurns et al. 2008 suggesting that non-cool core clusters suffered early majormergers destroying nascent cool cores.

On the Origin of Cool Core Galaxy Clusters: Comparing X-Ray Observations with Numerical Simulations