Dark matter reconstruction of the multiple cluster system A901/902 in orange-red colour scale derived from weak-lensing analysis (Heymans et al. 2008). Cluster members as a result of the biweight analysis (Sect. 3.1) are indicated with black diamonds. The four big crosses indicate the subcluster centres of A901a, A901b, A902 and SW group (from top left to bottom right), respectivel.y The radii of the 4 big circles are equal to the virial radii r₂₀₀ H08 (see Table 2).