Concentration as a function of sSFR. Each panel shows the scatter plot of the sSFR–C relation for the stellar continuum emission and three spectral lines. Each point represents a galaxy, colour-coded according to the morphological group they are belong to. AGNs are marked with a golden star. The average uncertainties of C for the different galaxy groups are shown in the top-right corner of each panel. We calculate the standard deviation of sSFR for each galaxy population.