Similar to Fig. A.2, but using the observed intensity profile from Fig. 6. Left panel: bias in the sampled radius caused by the gap at 0.2′′, shown by the vertical dashed line. Right panel: resulting deviation in velocity expected by this bias in red. For contrast, the blue line shows the deviations expected from a pressure gradient, here using the normalized radial gradient of the intensity as a proxy. The recovered δv_rot therefore is a combination of these two effects.