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 β-model to the high-resolution HRI data gives rc = 103 ± 12 h70-1 kpc and β = 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 kBTe = 10.4 ± 1.8 h701/2 keV. Extrapolating the gas density profile out to the virial radius (Rv = r178 = 2.9 Mpc), we derived a gas mass of Mg(r < Rv) = (4.0 ± 0.2) × 1014 h70-5/2 M⊙. Within the hypothesis of hydrostatic equilibrium, the corresponding extrapolated total mass for this source is: Mtot(r < Rv) = (1.8 ± 0.4) × 1015 h-1 M⊙, which corresponds to a gas fraction of fgas = 0.22 ± 0.06 h70-3/2. 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.
- Cosmology: observation
- Galaxies: clusters: individual: RX J2228+2037
- Galaxies: intergalactic medium
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science