Example of the stellar population spectral fitting. (a) and (c): aperture 01 (nucleus of the galaxy, N-S slit) fitted with BC03 and V15 models, respectively, and (b) and (d): aperture 13(N-S slit), also fitted with BC03 and V15 models, respectively. In each figure, top left panel: observed spectrum inblack, and the fitted synthetic spectrum in red. The regions marked in green represent masked intervals, ignored by STARLIGHT because of the presence of emission lines. Bottom left panel: residual of the difference between the two. Right panel: star formation history (SFH), which means the contribution of each population age and metallicity to the final synthetic spectrum.