Toomre diagrams for m12i LSR0 for stars passing traditional cut-based selection criteria, see Fig. 1 for the truth-level plots. The velocity based criterion in Figs. 1a and 1b introduces an asymmetry in the Toomre plane, which is absent in Fig. 1c. Only the V selection is possible with Gaia DR2 without cross-matching with other catalogs. The purities and efficiencies of all methods are presented in Table 1.