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 \pm 0.1 .