Position–velocity diagrams along the disk major axis in the C¹⁸O emission (panel a) and the ¹³CO emission (panel c). Panel d: zoom-in of panel c. Blue and red data points show the measured peak positions in different velocity channels. Rotational profiles measured from the data points in panels a and d are shown in panels b and e. Green solid lines show the best-fit power-law functions of the rotational profiles. Contour levels are from 3σ in steps of 3σ in panel a, where 1σ is 6.7 mJy Beam^-1, and the levels are from 3σ in steps of 5σ in panels c and d, where 1σ is 7 mJy Beam^-1. In the P–V diagrams, vertical and horizontal dotted lines denote the systemic velocity of V_LSR = 7.04 km s^-1 and the stellar position, respectively, and gray rectangles in the bottom right corners show the angular and velocity resolutions.