HCO⁺ emission integrated from −50 to 50 km s⁻¹. Red and blue contours mark the redshifted (5 to 45 km s⁻¹) and blueshifted (−5 to −45 km s⁻¹) HCO⁺ emission, respectively. Contours correspond to 5 σ_rms emission and the velocity ranges are given relative to the source velocity (−3 km s⁻¹). Black arrows mark the cuts for the PV diagrams (Figs. 5 and 6) and the ticks mark distances of 50 arcsec along the arrows.