Relation between Φ₀ and the concentration c = log(r_t/r_c). The continuous, dashed, and dotted lines represent, respectively, the theoretical prediction with a mass function slope α = 0.0, α = −1.0, and α = −2.0, while the black circles show the constrained values of Φ₀ and c for the analyzed clusters. The blue triangles show the King concentration from the Harris (1996) catalog (2010 edition), while the orange squares and green stars are computed using the core radius from the Harris (1996) and Baumgardt (2018–2023) catalogs respectively, and the tidal radius from Webb et al. (2013).