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		| Paper: | Distant Massive Clusters and Cosmology |  
		| Volume: | 176, Observational Cosmology: The Development of Galaxy Systems |  
		| Page: | 51 |  
		| Authors: | Donahue, Megan |  
		| Abstract: | We present a status report of our X-ray study and analysis of a complete sample of distant (z = 0.5-0.8), X-ray luminous clusters of galaxies. We have obtained ASCA and ROSAT observations of the five brightest Extended Medium Sensitivity (EMSS) clusters with z > 0.5. We have constructed an observed temperature function for these clusters, and measured iron abundances for all of these clusters. We have developed an analytic expression for the behavior of the mass-temperature relation in a low-density universe. We use this mass-temperature relation together with a Press-Schechter-based model to derive the expected temperature function for different values of Ω_M. We combine this analysis with the observed temperature functions at redshifts from 0-0.8 to derive maximum likelihood estimates for the value of Ω_M. We report preliminary results of this analysis. |  
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