Velocity channel maps for C¹⁷O J = 3 − 2 (contours), superposed on the 0.87 mm continuum image (grey-scale; Fig. 1). The highlighted panel with green contours represents the systemic velocity of 4.2 km s⁻¹. Blue and red contours indicate blue- and red-shifted emission with respect to the systemic velocity, respectively. In each panel, the contours start at 4σ (σ = 10 mJy beam⁻¹ per channel), following a step of 3σ, and the mean velocity of each channel is also presented in units of km s⁻¹. The yellow and white stars show the positions of Oph-IRS67A and B, respectively. The grey diamond denotes the location of the high-density region.