Left: adaptively smoothed 0.4–3.0 keV image of XLSSC 122, combining the MOS and PN data, with nearby point sources masked. Some artifacts due to the PN chip gaps remain visible. Cyan circles show our estimates of r₅₀₀ and r₂₀₀ from Sect. 3.7. Right: iJK image withsmoothed X-ray surface brightness contours overlaid in white. The outermost contour approximately corresponds to r₅₀₀. Galaxies that were photometrically identified with the cluster redshift (photo-z’s between 1.7and 2.1) by Willis et al. (2013) are circled in green. Magenta contours show the 68.3 and 95.4 per cent confidence regions for the centre of a symmetric cluster model fit to the CARMA data (see Sect. 3.5).