Cosmology and Astrophysics with the Most Massive Intermediate redshift Clusters

The most Xray luminous and massive galaxy clusters are the most interestingobjects for astrophysical and cosmological studies. Completing our REFELX IIcluster survey, we added 10 of the most luminous clusters in the redshift rangez0.30.5 at dec<40. This category of clusters has already received tremendousattention as witnessed by a series of studies on cluster structure, lensingproperties, SZ observations, galaxy population and dynamics. They are also themost important cosmological probes at the intermediate redshift to tracelargescale structure evolution, and to constrain cosmological parameters.Therefore we propose XMM observations of the 7 remaining luminous clusters to asufficient depth to precisely assess their physical properties. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]