Squared angular velocity (solid lines) evaluated in the central parts of the equatorial plane for the first three differentially rotating models displayed in Fig. 13, that is with Ψ = 2, , and χ = 0.04,0.16,0.36 (from bottom to top). Dashed lines indicate the asymptotic behavior at small radii, characterized by solid-body rotation, that is constant angular velocity. Dotted lines represent the angular velocity associated with the circular orbit of a single star, evaluated on the equatorial plane for the same models (from top to bottom). For the first two models , while for the third in the inner part, where the toroidal structure is present (the black filled circle marks the position where ).