Intensity-weighted velocity (moment 1) maps of all three CO isotopologue emission lines imaged for this analysis: CO (2–1) (left), ¹³CO (2–1) (center), and C¹⁸O (2–1) (left). The horizontal gray lines in the bottom-left corners represent a length scale of 1000 au, and the pink ellipses in the bottom-right corners represent the beam size. Black contours denote the continuum emission (5σ) from the protoplanetary disks. The locations of structures A, B, and C and the nearby source BHB2 are marked on the maps.