Same as the middle panel of Fig. 19 but adding a comparison with the trends of SFE_dense as a function of the velocity dispersion of the gas (σ) predicted by the model of Meidt et al. (2020). This model foresees different locations of galaxies in the SFE_dense − σ parameter space depending on the fraction of dense gas (F_dense) and, also, on the total molecular gas column densities (Σ_mol). Symbols are the same as in Fig. 17. Vertical and horizontal error bars at the lower-right corner account for the typical uncertainties, which amount to ±0.13 dex and ±0.06 dex, respectively.