Sample of member galaxies divided into sectors along the major (blue line) and minor (red line) axes for M1206 following the steps introduced in Sect. 4. The dashed yellow circle represents the half-mass radius R_hm. The sectors are identified as sector A in blue, sector B in orange, sector C in green, and sector D in red. If rotation were responsible for the observed flattening, gradients in the line-of-sight galaxy velocity distribution would be expected along the major axes and not along the minor axes.