SZ and X-ray combined analysis of a distant galaxy cluster, RX J2228+2037

We have performed a combined analysis of X-ray and Sunyaev-Zel'dovich data in the direction of the distant galaxy cluster, RX J2228+2037. Fitting a beta-model to the high-resolution HRI data gives r(c) = 103 +/- 12 h(70)(-1) kpc and beta = 0.54 +/- 0.03. The dependency of the Sunyaev-Zel'dovich effect with respect to the gas temperature allows us, through the additional use of the 21 GHz data of the cluster, to determine k(B)T(e) = 10.4 +/- 1.8 h(70)(1/2) keV. Extrapolating the gas density profile out to the virial radius (R-v = r(178) = 2.9 Mpc), we derived a gas mass of M-g(r <R-v) = (4.0 +/- 0.2) x 10(14) h(70)(-5/2) M-.. Within the hypothesis of hydrostatic equilibrium, the corresponding extrapolated total mass for this source is: M-tot(r <R-v) = (1.8 +/- 0.4) x 10(15) h(-1) M-., which corresponds to a gas fraction of f(gas) = 0.22 +/- 0.06 h(70)(-3/2). Our results on the temperature and on the cluster mass classify RX J2228+2037 among the distant, hot and very massive galaxy clusters. Our work highlights the power of the association of galaxy cluster mapping observations in X-ray and the SZ effect to derive the cluster's physical properties, even without X-ray spectroscopy.