a) Observed position-velocity diagram from the ¹²CO J = 2−1 map along the north-south direction across GW Ori. The offset refers to the distance along the cut from GW Ori. The contours start at 0.15 Jy beam^-1 (3σ) with an interval of 0.05 Jy beam^-1 (1σ). The dotted, dashed, and dash-dotted lines show a Keplerian rotation curve with a central mass of 3.9 M_⊙ with disk inclinations of 20°, 40°, and 60°, respectively. b) Same as in panel a), but for the modeled position-velocity diagram with a disk inclination of 35°.