Chemo-dynamical stellar populations of Sculptor. (a) and (d) panels: normalized metallicity and l.o.s. velocity distribution of the spectroscopically observed member stars of Sculptor alongside the median models (dashed colored lines) resulting from the fit of Sect. 4.1. Red, blue, and green indicate the MR, MP and third populations, respectively. Black shows the sum of the three components, as indicated in the legend. Bands indicate the 1σ confidence intervals. (b) and (c) panels: distribution of stars in the v_los versus [Fe/H]/R versus v_los planes. In each panel, the stars are color-coded by the population to which they have the highest probability of belonging, red for the MR, blue for the MP and green for the third population, as indicated in the legend. The systemic velocity of Sculptor is indicated with straight dashed lines.