Inferred SFH of JP×G^r16.5_5kpc sample for stars brighter than r = 4.2 mag, using Grid E, which simultaneously fits solar-scaled and α-enhanced isochrones (indicated as [a/Fe]=0.0 and [a/Fe]=0.4, respectively, in the panel titles). The grey histograms in the upper and right panels show the marginal distributions of age and metallicity, respectively. The red and blue error bars above the histograms represent the full width at half maximum (FWHM) of the age and metallicity uncertainties, as estimated in Appendix C. The dashed and dash-dotted lines highlight the two candidate populations that we consider to be detected.