AAS 205th Meeting, 9-13 January 2005
Session 161 Cluster Evolution and Large Scale Structure
Oral, Thursday, January 13, 2005, 10:00-11:30am, Sunrise

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[161.05] Multiwavelength Studies of Cluster Evolution from z=1 to the Present

A. K. Hicks (University of Colorado at Boulder)

Clusters of galaxies, as the largest virialized structures in the universe, have long been regarded as valuable cosmic laboratories that enable us to conduct direct investigations of the history of baryons in the cosmos. In particular, the study of clusters over a broad range in redshift provides us with invaluable information on the progression of large-scale structure formation over time.

We have performed an extensive analysis of Chandra X-ray observations of 13 moderate redshift (0.2 < z < 0.6) EMSS-CNOC clusters, including the determination of X-ray temperature profiles, spatial variations in the intra-cluster medium, and mass estimates. The purpose of these studies is twofold. We compare X-ray mass estimates to velocity dispersion and weak lensing mass estimates of this sample, with the objective of employing these clusters as calibrators of a relationship between mass and optical richness. We also utilize the X-ray and optical properties of the CNOC clusters as a basis for comparison in conducting high redshift investigations of cluster properties.

We contrast this moderate redshift sample with a set of higher redshift clusters. This second sample consists of six high redshift (0.64 < z < 1.0) clusters of galaxies discovered via the Red-sequence Cluster Survey, and observed with the Chandra X-ray Observatory. With these data we explore differences between the properties of X-ray and optically selected clusters, as well as the evolution of cluster properties with redshift, specifically as applies to the Lx-Tx relationship and spatial variations in the intra-cluster medium. Preliminary masses were determined for four clusters from the high redshift sample, which are reported and compared to SZ mass estimates.

This work was supported by a NASA Graduate Student Research Program (GSRP) fellowship, as well as Chandra Guest Observer grants GO2-3158X and GO2-3185X.

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© 2004. The American Astronomical Society.