Luminosity function of the RC region for two synthetic populations, both located at 8.2 kpc. The red one has been simulated assuming constant Star Formation History between 8 and 13 Gyr ago, while the blue one has a single burst 1 Gyr ago, making up 5% of the total stellar mass. The light blue shaded histogram shows the fraction of 1 Gyr old stars, over the total (red+blue), according to the scale on the right y-axis.