Histograms of the velocity dispersion amplitudes σ_k (k = 2, left panel) and of the normalised phase angles ϕ_k/T_k (k = 2, middle panel and 4, right panel) for the 7 galaxies brighter and fainter than M = −20.7 mag (red and blue colours, respectively) for the THINGS sample. The sub-samples are the same as when splitting between high (red) and low (blue) projected maximum velocity (see Sect. 5.2.4). The grey histograms are the total distributions from Fig. 5.