Top: distribution of the surface density Σ and the best-fit model with a lognormal function (continuous red line). Middle: stellar density as defined in Eq. (3) as a function of the star mass. The black and red lines indicate the median density of the whole stellar sample and the ten most massive stars, respectively. The continuous lines represent the best value, while the dashed lines represent their error bars. Bottom: evolution of the mass segregation ratio, Λ_MSR, for the N_MST most massive stars. The top x-axis indicates the lowest mass star m_L within N_MST and the dashed line corresponds to Λ_MSR = 1, i.e., no mass segregation.