AAS 203rd Meeting, January 2004
Session 30 Galaxy Clusters and Large Scale Structure I
Oral, Monday, January 5, 2004, 2:00-3:30pm, Centennial I/II

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[30.01] Massive Galaxy Clusters - New Insights from Hubble and Chandra

G.P. Smith (Caltech & Durham), J.-P. Kneib (Caltech & OMP Toulouse), I. Smail, P. Mazzotta (Durham), H. Ebeling (Hawaii), O. Czoske (OMP Toulouse & Bonn)

Massive galaxy clusters contain vast quantities of luminous and non-luminous material, including dark matter, X-ray emitting plasma and stars. The high projected matter densities reached in these deep (and rare) potential wells render them powerful gravitational lenses, causing the appearance of more distant galaxies to be magnified and distorted. The superb image quality of Hubble Space Telescope (HST) observations offers uniquely precise constraints on the distribution of matter in these spectacular systems. I will present new results from a systematic survey of ten X-ray luminous clusters at z=0.2. Our sensitive high-resolution HST imaging of the cluster cores is essential to detect and measure reliably the lensing signal in this objectively selected cluster sample. I use a sophisticated ray-tracing code to interpret this signal, and thus to measure the mass and structure of the cluster cores. Analysis of archival Chandra observations of the same clusters complements the lensing analysis and allows us to relate the details of the total cluster matter distribution to the thermodynamics of the intra-cluster medium. In summary, we find that 70% of X-ray luminuos clusters at z=0.2 are dynamically immature and have likely experienced infall from the field in the previous 2-3Gyr. The normalization of the mass-temperature relation for the immature clusters is 30% hotter than for the mature clusters. I will briefly discuss the implications of these results for large-scale structure, including the normalization of the matter power spectrum and the evolution of massive clusters.

The author(s) of this abstract have provided an email address for comments about the abstract: gps@astro.caltech.edu

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.