CDF of the most massive halo that is expected to be found in the redshift interval of 0.5 ≤ z ≤ 1.0 in an survey area of A_s = 22 735 deg². The dashed-dotted lines illustrate the uncertainty in the CDF due to the imprecision of the WMAP7 value of σ₈. The vertical shaded regions denote the values of the mass for which the CDF takes a value equal to nσ with n ∈  [ 1,5] , as labelled in the panel. We also added for reference the mass of ACT-CL J0102 (red errorbar), the most massive known cluster in the given redshift range, where the two small red arrows point at the values of the CDF stemming from the upper allowed mass for the distributions based on σ₈ (lower arrow) and σ₈ − Δσ₈ (upper arrow).