Schematic representation of the nuclear warped disk (corresponding to the red substructure in Fig. 15). The black star is the center of M31. The x axis represents the line of sight, and the yOz plane the plane of sky. The filled pink color refers to the inner nuclear disk, and also to the end of the warped region. The dashed lines represent two perpendicular diameters of the substructure. One of the two coincides to the major axis of the projection. The plain lines show where the second diameter would be if the substructure was not inclined (i.e., fully in the plane of sky). The successive circles in the middle are a simple representation of the warped region, defined as a set of misaligned circles with continuously varying inclination and position angles. For visibility reasons, the different parts of the substructure are not to scale with respect to each other, and only a few of the misaligned circles have been drawn. Bright red line at the outer bound of the substructure shows where the warped disk supposedly ripped from the 1 kpc ring. The nuclear warped disk is located inside the 1 kpc radius of M31, superposed with the ∼1 kpc inner ring and the main disk.