High Redshift Galaxy Clusters and the Value of Omega

The goal of our project is to quantify the number of massive, highredshiftgalaxy clusters, with the aim of constraining the density parameter of theUniverse by employing the extreme sensitivity of the highmass end of thecosmological mass function to Omega. For that purpose, we propose a twofoldapproach: 1) measure the temperature of a sample of known highz (0.4<z<0.7)clusters detected in the SHARC Xray survey, and 2) search for the Xrayemission associated with more distant cluster candidates (z>1) thought to berelatively massive due to either their lensing effects or theirSunyaevZel.dovich signal.NOTE: Soc enhance request: the pn/filter might need to be changed if the optical loading proves not to be a problem. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]