Core position as a function of wavelength for observed jet and observed disk models. Crosses indicate the core position relative to the central BH at 13.6 mm, 7 mm, and 3.5 mm (22/43/86 GHz) for observed jet models. Colors represent different inclination angles. Stars indicate the core positions for observed disk models. All models have an orientation of PA = 0°. Solid lines (jets) and dashed lines (disks) show the best-fit power law using a least-squares fitting method. Error bars represent 1σ errors in the core position data. Parameters, fitting errors and χ² are summarized in Tables D.1 and D.2 in the support material. The legend indicates the inclination (i) and power-law index (p) for a given model.