Line integrated ¹²CO (3 →2) synthetic maps and cuts. Left panel: spatial distribution of the warm background emitting layer. Middle panel: spatial distribution of the cold foreground absorbing layer. Right panel: position-intensity diagram along the two cuts indicated by the gray lines crossing the ionizing star. The upper panel shows the horizontal cut and the lower panel shows the diagonal cut. The orange curve is showing the column density of the emitting background layer, the green curve shows the column number density of the absorbing foreground layer and the blue curve indicates the combined column density of both layers.