Results of the propagated SFB model. Left: same as the second and fourth row of Fig. 2, for the evolution of SFR and [M/H], Right: age distributions are displayed in the top panel for different radial ranges of 6–7, 7–9 and 9–10 kpc, corresponding to the equivalent observational sub-samples in inner, local, and outer bins shown in Fig. 6 of Sahlholdt et al. (2022); observations (red curves) are compared to model results (blue curves). In the lower panels, age–metallicity relations of the model (green isodensity contours) are compared to half-maximum density contours from observations of Sahlholdt et al. (2022) (dotted and dashed red curves indicate the high-ɀ_max and low-ɀ_max part of observations in each radial range).