a) Radial velocities of stellar absorption lines in the wavelength region 4700−5450 Å measured by Whitmore et al. (1984): black dots. The bar is the 1σ error of their data. In all panels, the open circles are the radial velocities of the near-IR stellar Ca ii absorption lines shown in Fig. 1b; the continuous lines present the CO radial velocities published by Sofue (1998). b) radial velocities of stellar clusters (within |z|    ≲    500 pc) from Konstantopoulos et al. (2009): black dots, triangles: cluster Nos. 108, 112, 2, 125, 126 with a high radial velocity, seen in the direction of complex B. c) radial velocities of planetary nebulae (within |z|    ≲    500 pc) from Johnson et al. (2009): black dots.