Bar age measurement method. We illustrate the method described in Sect. 3, analogous to Fig. 2 in de Sá-Freitas et al. (2023a). We show the nuclear disc and representative ring regions, from which we derive the SFH of the original data in the nuclear disc region (red) and the representative region (green). We proceed to subtract the main disc SFH from the original one, and the difference is considered the nuclear disc SFH (blue). We then use the ratio ND/MD to time the moment of bar formation (right plot, orange).