A χ²-like test defined by δ_M for best-fit curves to the RVD profile of sample SII (see Fig. 3, bottom panel) shown as a function of the central mass M. The phase-space support used to obtain these results was fixed by u_a = 18   kpc and u_b = 300   kpc, and the fitting region was limited to r > 22   kpc. One can distinguish 5 accumulation curves that correspond to various degrees d of polynomials used to approximate the phase distribution function (here, d = 4,5,6,7,8). These curves were compared with best-fitting hyperbolas in the inset panel. Abscissae of crossing points of the corresponding asymptotes suggest the presence of a lower bound for mass in the limit of large d. The red dots represent minimum values of δ_M found at M = 2.4 × 10¹¹  M_⊙ and, to compare with, at M = 1.0 × 10¹²  M_⊙ (for d = 8 points with u_b = 240   kpc were also included).