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 \pm 12 h _ { 70 } ^ { -1 } kpc and \beta = 0.54 \pm 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 \pm 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 \pm 0.2 ) \times 10 ^ { 14 } h _ { 70 } ^ { -5 / 2 } M _ { \odot } .
Within the hypothesis of hydrostatic equilibrium , the corresponding extrapolated total mass for this source is : M _ { tot } ( r < R _ { v } ) = ( 1.8 \pm 0.4 ) \times 10 ^ { 15 } h ^ { -1 } M _ { \odot } , which corresponds to a gas fraction of f _ { gas } = 0.22 \pm 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 .