The XXL Survey - XVII. X-ray and Sunyaev-Zel’dovich properties of the redshift 2.0 galaxy cluster XLSSC 122
Résumé
We present results from a 100 ks XMM-Newton observation of galaxy cluster XLSSC 122, the first massive cluster discovered through its X-ray emission at z ≈ 2. The data provide the first precise constraints on the bulk thermodynamic properties of such a distant cluster, as well as an X-ray spectroscopic confirmation of its redshift. We measure an average temperature of kT = 5.0 ± 0.7 keV; a metallicity with respect to solar of Z/Z⊙ = 0.33−0.17+0.19, consistent with lower-redshift clusters; and a redshift of z = 1.99+0.07-0.06, consistent with the earlier photo-z estimate. The measured gas density profile leads to a mass estimate at r500 of M500 = (6.3 ± 1.5) × 1013 M⊙. From CARMA 30 GHz data, we measure the spherically integrated Compton parameter within r500 to be Y 500 = (3.6 ± 0.4) × 10−12. We compare the measured properties of XLSSC 122 to lower-redshift cluster samples, and find good agreement when assuming the simplest (self-similar) form for the evolution of cluster scaling relations. While a single cluster provides limited information, this result suggests that the evolution of the intracluster medium in the most massive, well-developed clusters is remarkably simple, even out to the highest redshifts where they have been found. At the same time, our data reaffirm the previously reported spatial offset between the centres of the X-ray and SZ signals for XLSSC 122, suggesting a disturbed configuration. Higher spatial resolution data could thus provide greater insights into the internal dynamics of this system.Key words: galaxies: clusters: individual: XLSSC 122 / galaxies: clusters: intracluster medium / X-rays: galaxies: clusters★ These results are based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the Chandra X-ray Observatory; and the Combined Array for Research in Millimeter-wave Astronomy (CARMA).★★ The reduced images and spectrum (FITS files) are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/620/A2