Measuring ICM Temperatures at Large Radii in Rich Clusters of Galaxies

The radial temperature profile of the Xray emitting intraclustermedium (ICM) is key observable in determining the total gravitationalmass of clusters of galaxies. To date different studies (ROSAT, ASCAand BeppoSAX) have found conflicting results regarding temperaturegradients in clusters. We propose to observe the outer clusterregions (i.e., > 50\\%60\\% of the virial radius), of three nearbyrelaxed clusters, to definitely assess whether a temperature decline ispresent in these regions and, in presence of a gradient, to determinethe slope of the temperature profile, which carries importantinformation on the thermodynamical status of the ICM. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]