Fig 4. The $r_{J_m^{\prime }}-{\rho }_c$ relation is independent on all the other cluster features, R_c, ρ_r, N_c, W, and H.

All data points collapse onto a single power-law curve, $r_{J_m^{\prime }}=A·{{\rho }_c}^{-\alpha }+b$. Least-square fitting gives α = 0.76 ± 0.03.