Colour − magnitude diagrams within three elliptical radius annuli. The first annulus corresponds to an elliptical radius equal to 1 r_eff, the second between 1 and 2 r_eff, and the third beyond 2 r_eff, shown from left to right, respectively. In the left panel, we overplot Padova isochrones with ages of 20 Myr, 40 Myr, 60 Myr, 80 Myr, and 150 Myr, and for all isochrones a Z metallicity of 0.001. Also shown in the left panel with the error bars are the photometric errors. In the right panel, we show with open circles the galactic foreground contamination.