Dynamical modeling of 9io9. We show the source plane CO (J = 4 → 3) emission averaged over 88 km s⁻¹-wide channels spanning −350–350 km s⁻¹. The color scale saturates at 4 mJy. Contours show the equivalent line emission extracted from the best-fitting model datacube, describing a rotating ring with inner radius 160 pc, outer radius approximately 2.5 kpc, and maximum deprojected velocity 360 km s⁻¹. Contours show the corresponding emission in the model cube, starting at 0.5 mJy and increasing in steps of 0.5 mJy.