Projected phase-space diagram of the galaxies in the field of PSZ2 G040.03+74.95 (Abell 1831) and member selection. The distribution is clearly bimodal. The initial candidates within a radial distance of 3θ_{MMF3, 500c} from the X-ray peak, and within a window in velocity of ±Δ_{vrf, PSZ2} with Δ_{vrf, PSZ2} = 12 000 km s⁻¹ from the nominal PSZ2 velocity, are shown in orange. The candidate virialised members that passed the first cleaning procedure (in blue) are selected within a radial distance of r_200c and a rest-frame velocity window of ±κσ_los(R), with κ = 2.7. In green and red, we show the result of the cleaning procedure on each sub-clump. For visualisation purposes, radial distances are here shown assuming the same cluster redshift (the result of the first cleaning procedure) for all galaxies. For this cluster, all members selected at the first step (violet) are also virialised members (blue, which is superimposed on violet).