Observed C¹⁸O (2−1). Left: pure Keplerian rotation curves (v ∝ R^-0.5, red and blue) and infall (v ∝ R^-1, green) are overlaid on the PV diagram. This suggests that the emission may be rotationally supported with M_∗ ~ 0.1−0.2  M_⊙. Center: C¹⁸O velocity map (moment 1, halftone) and intensity integrated (moment 0, contours) maps. Contours are in steps of 3σ, 5σ, 10σ, 15σ, 20σ and 25σ with σ = 13 mJy beam^-1. VLA1623A and B’s positions are marked with a square and triangle, respectively. Orange and blue lines indicate the image-space PV diagram cuts at PA = 35° (left) and 125° (right), respectively. Right: lack of velocity gradient suggests no outflow contamination on the C¹⁸O emission. In both PV diagrams contours are in steps of 3σ, 5σ, 10σ and 15σ where σ = 19 mJy beam^-1 and the black lines indicate the systemic velocity and position of VLA1623A.