Position-velocity diagrams along the major axis. Velocity 0 corresponds to the systemic velocity of the galaxy, V_sys(LSR) = +225 km s⁻¹ (Neininger et al. 1998), and the position (0,0) is marked by a star. The contour levels are at 30%, 50%, 70%, 90%, and 95% of the peak intensities. The white contours represent HCN(1–0), HCO⁺(1–0), HCN(4–3), and HCO⁺(4–3), while the black contours correspond to the CO(3–2). Color scale shows the normalized intensity of CO(1–0).