Comparison of FWHMs of ionised- and molecular-gas emission lines, estimated from a single-Gaussian function for the DP sample galaxies. The FWHMs of the ionised-gas emission lines (x-axis) measured inside the 3″ SDSS fibre are estimated by Chilingarian et al. (2017). The FWHMs of the CO line (x-axis) are measured as described in Sect. 3.3.3. The black dashed line denotes y = x. Error bars are estimated from the single-Gaussian line fitting. Stars indicate galaxies classified as mergers. The markers are coloured according to the BPT classification (see Sect. 3.3.1): SF in yellow, COMP in magenta and AGN in black. We mark galaxies for which we succeed in applying a combined line fit (see Sect. 3.1) by red circles. The four ULIRGs of the DP sample are marked with green circles. For the galaxy DP-1, the CO-FWHM is estimated both inside the 3″ SDSS fibre and for the entire galaxy, and the two points are connected with a green dashed line.