A comparison of central temperatures of the intracluster gas determined   from X-ray and SZ measurements
  A combination of the X-ray imaging and SZ measurements of clusters permits an indirect determination of the radial temperature profiles of intracluster gas, which requires no assumption about the dynamical properties and the equation of state for clusters. A comparison of such a derived gas temperature with that given by the X-ray spectral analysis constitutes an effective probe of properties of intracluster gas. Using the available data of 31 clusters in literature, we have performed the first comparison of the central gas temperatures provided by the two methods. The good agreement between these two independent temperature estimates suggests that the distribution of intracluster gas is essentially consistent with isothermality characterized by a mean polytropic index of gamma=0.9+-0.1. 
Tong-Jie Zhang and Xiang-Ping Wu