The color − magnitude diagram in the central region (r ≤ 600 kpc) of XMMU J2235. All sources in the field are shown, except for point–like sources. Filled circles are spectroscopic members and large empty circles show photo-z retained sources (0.96 < z < 1.82). Gray symbols (crosses and pluses) show spectroscopic and photo-z interlopers, respectively. The colored lines show the expected location of the red sequence at z ~ 1.4 based on Kodama & Arimoto (1997) models for different formation redshifts (z_f = 2, 3, 5, as indicated). The slanted continuous line shows the 10σ completeness (for the overall catalog, considering AUTO apertures). The plotted z − H colors are derived from resolution-matched 1′′ aperture magnitudes, and error bars include the estimated error contribution from the resolution-matching procedure. Error bars are plotted only for retained sources.