Example of the fitting procedure used to search for systematic rotation of the galactic component in clusters of galaxies. Left: Projected spatial distribution of galaxies of Abell 2199, colour-coded according to their line-of-sight velocity relative to the cluster mean (v). The dashed contours represent three different cuts within which we performed the test, in order to monitor whether the velocity amplitude would increase or decrease and how the axis position angle changes with radius. Right: Corresponding sine fits, from which we extracted the parameters related to the largest scale (R) reported in Table 2.