Sketch of the proposed disk+halo model. a. View of the halo in projection onto the plane of the sky. The y axis is the projection of the disk rotation axis. The circle is the outer border of the spherical halo, while the green ellipse represents the disk. The red point indicates a generic LOS and the blue line is the intersection between the halo and the plane parallel to the disk axis and containing the given LOS. b. Cut of the disk+halo corresponding to the blue line in panel a. The green line denotes the disk seen edge on and the red line is the LOS indicated by the red dot in panel a. Points z₁ and z₂ are the intersections with the halo. The y′ axis is rotated by the angle ψ in the x, z plane with respect to the plane of the sky. The observer lies at z = −∞.