Metallicity distribution function of our sample. A two-component GMM model is superposed. The first component is centred at −0.76 dex with a standard deviation of 0.24 dex, while the second component is centred at +0.26 dex with a std of 0.10 dex. The blue dashed lines represents the Gaussian fit for the metal-poor population, while the red dashed lines are for the metal-rich population. The total model is displayed with a solid black line together with the 3 σ uncertainties.