Data points are measured stellar velocity dispersions of cluster members, color-coded according to their spectral ⟨S/N⟩. Green lines are 300 scaling relations randomly drawn from the posterior distributions of the σ_ap–mag scaling relation parameters, α, , Δσ_ap, obtained from fitting the data points (see Fig. 3). Optimized parameters are also quoted. Red and blue areas are obtained by projecting the 3D σ–L scaling relations from our previous lens models with no kinematic prior (see text). Some velocity dispersion measurements, which deviate significantly from the scaling relations, are marked with squares and circles and discussed in the text.