The Local Galaxy Cluster Mass Function of the Brightest Clusters in the Sky

Galaxy clusters have proven to be highly competitive and complementary cosmological probes. For the next major breakthrough more reliable mass estimatesand, therefore, a better understanding of cluster physics are essential. Wepropose to complete XMMNewton observations of a fluxlimited sample of the 63Xray brightest clusters in the sky to (i) take full advantage of virgul3Ms ofXMMNewton data already available, (ii) determine very precise gas temperatureprofiles, (iii) characterize merging clusters by direct comparison tosimulations, (iv) update the luminositymass relation, (v) construct the mostprecise local cluster mass function, (vi) improve constraints on OmegaM andsigma8 significantly, and (vii) provide a reliable statistical baseline for comparison to highredshift samples. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]