Northern Nucleus: comparison of kinemetry models for 2 different PAs and kinematic centres. It should be noted that the rotation curves do not differ significantly for the two different positions of the kinematic centre. Black circles indicate black hole positions; black stars represent the kinematic centre; the dashed white line traces the major axis of rotation. Left to right: velocity map, model, and residuals. First row: best-fitting kinematic centre from kinemetry analysis. The average residuals per pixel are 33.5 km s^-1. Second row: kinematic centre fixed at the position of the AGN. The average residuals per pixel are 35.3 km s^-1. Image size is 820 × 720 pc.