Galaxy cluster baryon fraction, cluster surveys and cosmology

The properties of nearby galaxy cluster limit the range of cosmological paramaters consistent with our universe. We describe the limits which arise from studies of the intracluster medium (ICM) mass fraction fICM and consideration of the possible sources of systematic error: (math formula) at 95% confidence. We emphasize that independent of Type Ia supernovae (SNe Ia) observation, this cluster study, taken together with published cosmic microwave background (CMB) anisotropy studies, indicates a non-zero quintessence or dark energy component ΩQ > 0. We then discuss future galaxy cluster surveys which will probe the abundance of galaxy clusters intermediate and high redshift. We investigate the sensitivity of these surveys to the cosmological density parameter ΩM and the equation of state parameter w of any quintessence component. In particular, we show that cluster survey constraints from a proposed large solid angle X-ray survey are compatable in precision and complementary in nature to constraints expected from future CMB anisotropy and SNe Ia studies.