Position-velocity diagrams for C¹⁷O and H¹³CO⁺ towards the disk-like structure direction (PA = 234°) and centred at the position of the geometric centre. Green and magenta dots represent low- (<1.7 km s⁻¹) and high-velocity (>1.7 km s⁻¹) emission peaks, respectively. Blue solid and dashed lines show the best fit for a Keplerian and an infalling velocity profile, respectively. The cut taken from the image data is shown in grey contours, ranging from 3σ (1σ = 10 mJy beam⁻¹) to the maximum value of each transition. Each adjacent contour represents an increment of the 20% of the maximum value.