092084

Clusters of galaxies are great objects to study cosmology and astrophysics.There are many cluster samples selected from ICM-based observations (X-ray andSZ). However the ICM-based selections are also ICM-biased e.g. X-rayselections are biased to cool core clusters. The results from these ICM-biasedsample can affect the constraints on the cluster cosmology and baryon physics.We select an optically rich cluster sample from the redMaPPer catalog. We findmost of them that uncovered by modern X-ray telescope are X-ray faint clusters.We request XMM observations for them in order to have a complete and unbiasedview of ICM properties. The results will provide helpful guidance for futuresurveys. [truncated! Please see actual data for full text]