Distribution in the mass–redshift plane of all the clusters published in the Planck, SPT, and ACT catalogues. Filled circles: Planck clusters with available redshifts (Planck Collaboration VIII 2011; Planck Collaboration XXIX 2014; Planck Collaboration XXVII 2016); crosses: SPT (Bleem et al. 2015); plus symbols: ACT (Hasselfield et al. 2013). Masses in the Planck catalogue are derived iteratively from the M₅₀₀ − Y_SZ relation calibrated using hydrostatic masses from XMM-Newton; they are not corrected for the hydrostatic equilibrium (HE) bias. In the figure the Planck masses are multiplied by a factor of 1.2 (i.e. assuming 20% bias). The blue and orange open squares identify the Low-z and High-z samples considered in this study (see Sect. 2). The clusters that are part of the Low-z PXI sample are shown as filled blue squares.