RXJ1821+6828: Temperature Distribution and Metallicity for a z=0.81 cluster

There are only a few Xray selected clusters with redshift greaterthan 0.8, making each of them a prime target of studies of clusterformation. We propose to observe the cluster RXJ1821+6828 at z0.8108,found in the NEP region of the ROSAT AllSky Survey, to derive theXray temperature distribution, measure the iron abundance, andobtain an high quality image. Temperature information for highzclusters places strong constraints on cosmological models and onthe physical processes in the early epochs of our universe. Existinglower resolution Xray images indicate that these clusters are oftenfilamentary with the Xray flux generated at the impact point of the truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]