Synthetic channel maps of the v(1−0)P08 line (4.73587 µm) of the HD 100546 CSD+CPD model for the high external irradiation case (a) and for the low external irradiation case (b). In both cases, the CPD outer radius R_out = R_Hill (1.62 au). The PRODIMO model used as input for SimMetis is in the top row of each subfigure. The ellipses in the upper-leftmost panel indicate the inner and outer edges of the gap at 4 and 19 au, and the companion orbit at 15 au (dotted line). The corresponding simulated METIS observation panels represent six detector integrations of 10 s each in the bottom row of every subfigure. The white contour lines represent the signal-to-noise ratio values (S/N) of 3, 5, and 10. The velocity offset is relative to the stellar reference frame.