Synthetic model results for [Mg/Fe] vs. [M/H] distributions including stellar migration produced by the delayed two-infall model with second infall enrichment for inner radii (left panels) and without second infall enrichment (right panels). The radial migration prescriptions are from Frankel et al. (2018). The stellar yields are from François et al. (2004). Purple filled pentagons are the mock data from the synthetic model. Mock and observational data for the MSTO subsample are plotted as in Fig. 8, with density normalisation done independently for each panel. Upper panels: stars older than 9 Gyr. Middle panels: stars with ages between 9 and 5 Gyr. Bottom panels: Stars younger than 5 Gyr.