Contour plots of normalized flux at the time of the first (left panel) and second (right panel) PA flip in the two-dimensional parameter space of q versus y_j. We note that there is no PA flip when q ≃ 1, which is not marked in the figure. In this group of calculations, we fixed θ_j = 0.1 radians and changed Γ. The numbers in parentheses on the horizontal axis represent the values of the corresponding Lorentz factors.