Channel-velocity maps of HCO⁺(3 − 2) in the velocity range [−500, 500] km s⁻¹ with steps of 50 km s⁻¹. Contours go from 6.5 mJy beam⁻¹ (5σ) to 56 mJy beam⁻¹ with a spacing of 10 mJy beam⁻¹. We highlight the significantly smaller spatial scale relative to the channel maps of the (1 − 0) line shown in Fig. 12. The synthesised beam is plotted in the bottom-left corner. North is up and east is to the left.