Combined RGB plot and channel maps for M16 and M17. Each panel displays the distinct velocity ranges (blue and red for the high-velocity blue- and redshifted emission, green for the bulk emission) as an RGB plot with contours of ¹²CO(3−2) emission overlaid. The contour levels are 5 to 68 K km s⁻¹ in steps of 9 K km s⁻¹ for M16 and 4 to 52 K km s⁻¹ in steps of 6 K km s⁻¹ for M17. The corresponding CO velocity is given in the upper-right corner. The exciting star clusters are indicated with a yellow star symbol. Examples of high-velocity blue- and redshifted [C II] gas not associated with the expanding bubble are indicated with blue and red arrows, respectively.