Outlier removal based on GC velocities and projected distances. Top: Line-of-sight velocities as a function of projected galactocentric distance for the full sample of 721 unique sources. Different colours refer to different samples. In case a source is found in multiple samples, only the velocity with the smallest uncertainty is shown. Bottom: Difference between m_N and m_N − 1 as a function of GC number N (left, see Eq. (1)) and the derivative (right). The vertical grey line indicates our chosen cut-off N_cut = 222, right after the last big jump as seen in the derivative. From this value, the corresponding v_max(R) curve was derived, which is shown as the grey dashed line in the top panel. The shaded regions show the curves when assuming N_cut ± 5.