Azimuthal Fourier coefficients of type-II plotted as a function of the outgoing frequency x for different choices of μ and μ′. Left panels show and right panels show . The damping parameter a = 0.001. Thin lines correspond to x′ = 1 and thick lines to x′ = 4. Solid, dotted, dashed, dot-dashed, and dash-triple-dotted lines correspond to k = 0,1,2,3, and 4, respectively. For notational brevity we simply dropped the M dependence on the y-title of the plotted functions.