Channel maps for the ¹²CO J = 2-1 molecular line. The white contour enclosing the line emission shows 5σ. The gray background contours indicate the scattered light emission, same as Fig. 1 (a), to highlight that the spiral spurs in the line emission closely follow the IR ring. The beam size of the high-resolution cube is plotted in the lower left corner. Note that we only show every second channel (200ms⁻¹), and the systemic-velocity channel is at 5.1 km s⁻¹. A movie of the ¹²CO channel maps can be found in the online resources.