Mean W velocity component as a function of galactocentric azimuth for RC stars at 13 <R(kpc)< 14. RCGs simulated using models A and B are plotted as dashed purple and solid blue lines. The fit to PPMXL data is given in black, the same as the fit in Fig. 5 in the bottom-left panel. The Gaia “observed” values are plotted in red. The shaded regions in blue and yellow represents the standard deviations of the W velocity for model B without and with Gaia errors. The line of nodes is defined to coincide with the Sun-Galactic center line (φ_w = 0).