Escape velocity determined using the LT90 method in rings of constant cylindrical R and z. The colour of the markers indicates the maximum probability value for v_esc. The colour map in the background shows expected isocontours for the escape velocity according to the McMillan17 potential, which assumes a spherical halo, but whose parameters we have updated with the values from Sect. 7.2. Volumes in which the 3σ levels enclose the background value are indicated with plus markers, the crosses indicate volumes in which the determined v_esc is higher than expected.