Integrated intensity image of the [C ii] line at 158 μm in color. Contours correspond to the tracers mentioned in the individual panels. The contour levels are ¹³CO(3−2): (3−8), (10−13), (15−18)σ with σ = 4.2 K km s^-1; CO(3−2): (3−8), 10, 15, 20, 25, 30, 32, 35, 38, 40 and 42 times σ = 5.1 K km s^-1; CO(4−3): (3−8), 10, 12, 15, 18, 21, 24 times σ = 8.6 K km s^-1; CO(6−5): 3, 5.5, 9.5, 11.5, 13, 15, 20, 25, 30, 35, 40 times σ = 5.4 K km s^-1; CO(7−6): 4, 6, 11, 15, 18, 20, 22, 24, 26 times σ = 8.2 K km s^-1; CO(11−10): 3, 5, 8, 10, 12, 15, 20, 22, 24, 26 times σ = 1.3 K km s^-1. HD 37903 is marked by a star symbol.