Results of the bisymmetric model of the V_R and V_ϕ velocity maps. Top: amplitudes A_R and A_ϕ of the bisymmetry. The axisymmetric component is also shown. Bottom: phase angle of the perturbation with respect to the Sun-GC direction. The shaded area represents the uncertainties. The horizontal dotted line marks the estimated bar orientation angle. The vertical dashed line and purple area show the estimated location of the bar corotation.