Distribution of v_ℓ at different distances and Galactic latitudes below the Galactic plane. The top left panel shows the dependence of v_ℓ on the distance toward the Galactic bulge color-coded according to on different Galactic latitudes. The dashed black line represents the approximate distribution of v_ℓ from Sanders et al. (2019), and the dotted light blue line represents the distance to the Galactic center. The top right and bottom left panels show insets for two bins from the top left plot, particularly for X bins at 5.67 kpc and 12.33 kpc, respectively, with the same color-coding as in the top left panel. All stars were selected within |ℓ| < 2 deg. For the same figure but for stars above the Galactic plane see Fig. D.10.