Parameter space of rotation velocity (VROT) and velocity dispersion (VDISP) from modeling the Hα cube of zC-400569 with SpacePar. The color-scale represents χ² values at different radii, given in the top label. The best-fit values are indicated with a cross and reported in the top label. The white contours correspond to percentage variations in χ² from the best-fit value (2%, 5%, 10%, and 30%). Similar plots are presented in Appendix A for CO data. The small values of the velocity dispersion suggests that this quantity cannot be reliably measured because the line broadening is entirely dominated by the observational effects of spectral and spatial resolution.