Moment 0 map (black contours at 3σ ≈ 43 mJy beam^-1 km s^-1 intervals) and moment 1 map (colour scale, velocities in km s^-1) of the C¹⁷O emission centred at IRS7B, integrated between − 11 km s^-1 and + 21 km s^-1. The colour bar indicates LSR velocities in km s^-1. The dashed grey line indicates the axis along which the PV diagram fits of Figs. 5–7 are made. The dust continuum emission is shown in green contours (logarithmically spaced between 2 mJy and 200 mJy).