CMD K_s vs. J − K_s with and without extinction correction. Red arrows show the position of the detected features. The black arrow indicates the reddening vector. The red continuous line corresponds to an isochrone of 13.5 Gyr and Z = 0.04 plotted over the de-reddened stars. Upper and lower panels show F1 and F2, respectively. Red dotted lines show different divisions of the data used to produce LFs. Accounting for atomic diffusion would reduce the age of the depicted isochrone ∼0.7 − 1 Gyr (see main text).