Galaxy cluster mass measurements based on joint X-ray and Sunyaev Zel'dovich effect data

Galaxy clusters trace the growth of structure of the universe and their abundance and evolution reflect the underlying cosmological parameters, such as OM, sigma8, and the dark energy equation of state parameter. A new analytic model was developed which describes the physical properties of the intra-cluster medium (ICM) (Bulbul et al., 2010). The model has the advantage of simultaneously fitting X-ray and Sunyaev Zel'dovich Effect (SZE) data. A method of the joint analysis of X-ray and SZE data using the self-consistent model allows for the measurement of the gas mass fraction without the need to impose external priors on the cosmological parameters.;Massive clusters are expected to trace the matter content of the universe. The cluster gas mass fraction radial profile was measured out to r500 for 25 relaxed clusters using Chandra data. When combined with the stellar mass fraction, the cluster baryon fraction at r500 is 0.177+/-0.024 agrees with the cosmic baryon fraction measured by WMAP (OB/O M = 0.167+/-0.006; Komatsu et al., 2011). This verifies that massive relaxed clusters accurately trace the primordial content of the universe provided that the measurement of the gas mass fraction is determined at large radii.;The gas mass fraction is an essential astrophysical quantity for probing cosmological questions. The behavior of the gas mass fraction as it evolves with redshift has never been determined observationally. Using the joint X-ray and SZE analysis method, the redshift evolution is measured with minimal assumptions about the cosmology for 25 clusters spanning a redshift range 0.09--1.06.;The joint analysis method can also be used to investigate discrepancies between the ICM pressure inferred from X-ray and SZE observations. Agreement between the SZE and X-ray pressure are within a few percent. The average of the ratio of the two pressures is 1.02 +/- 0.04. Therefore no evidence is found for the presence of significant sources of systematic uncertainty in the measurement of the ICM pressure from X-ray and SZE observations. Improvements to this dissertation may be made by expanding the sample and using better quality data.