Vertical (σ_z) velocity dispersion as a function of age. Middle panel: best-fit models for the AVR of the low- and high-[Mg/Fe] selection in age-v_z space, compared with the data used in the fit. Lower panel: AVRs themselves, and upper panel: age distribution of the [α/Fe] selected populations. Blue and red lines represent the best fit power-law models for stars in the low- and high-α sequence, respectively. The coloured bands in the lower panel show the 5th to 95th percentile credible intervals of the inferred σ_z−age relation. The AVR for each population is only shown in the range of the 0.05 and 0.95 quantile of its ages.