Kennicutt–Schmidt (KS) relation for CO samples. Top panel: KS relation using the total molecular-gas mass and the SFR of the all of the galaxies, and we normalise both quantities using the half-light radii. The DP sample is indicated with red dots, the EGNOG sample with blue dots, the COLD GASS sample with grey dots, the low-SF sample with black dots, the M sample with turquoise dots, and the ULIRG sample with green dots. Galaxies of the low-SF and COLD GASS samples showing AGN activity are marked with stars (see Sect. 3.3.1). Bottom panel: decomposition of the ten DP galaxies for which we succeeded in performing a combined fit (see Sect. 3.1). We show the decomposition in a zoomed-in image of the top panel, which we mark with a dashed box. We display blue (resp. red) squares for the blueshifted (resp. redshifted) component and connect the two components with a black dashed line. We use the SFR estimated by Hα emission of each component and the observed H₂ mass of each component and normalise them to the surface of the 3″ SDSS fibre. The three galaxies, classified as mergers, are marked with black plus signs. In both panels, dotted lines denote the constant t_depl of 0.1, 1, and 10 Gyr. The solid black line corresponds to a constant t_depl of 1.24 Gyr estimated using Tacconi et al. (2018) for the mean redshift and stellar mass of the DP sample. In both panels, error bars indicate the mean estimated uncertainties. However, in the lower panel, uncertainties estimated from the surface measurement are not included.