Position-velocity diagram for c−C₃H₂ 5_5,0 − 4_4,1 towards the disk-like structure direction (PA = 234°) and centred at the position of the geometric centre. The magenta dots represent high-velocity (>1.7 km s⁻¹) emission peaks. Blue solid and dashed lines show the best fit for a Keplerian and an infalling velocity profile, respectively, while the red dashed line represents an infalling profile for a central mass of 2.2 M_⊙. The cut taken from the image data is shown in grey contours, ranging from 3σ (1σ = 10 mJy beam⁻¹) to the maximum value. Each adjacent contour represents an increment of the 20% of the maximum value.