Probability density function of the concentration (Eq. (10)) at the different redshifts values given in each panel. Each set is divided into mass slices, and is color-coded accordingly. The shaded areas represent the data with 1σ error, while the straight lines indicate the best-fit model. The blue points and line represent the total sample not sliced in mass. For clarity, each line and its fit is shifted by 0.1 dex on the y-axis. This means that the constant C₀ assumes values of (+0.3, +0.2, +0.1, 0.0, −0.1, −0.2). The purple line is not shifted, and is thus the one with the proper normalization.