Spectral lines toward the protrusion. Upper panel: Spitzer 8 μm image of the protrusion. Red circles indicate the 12 positions that we used to extract line profiles and have an aperture of 16′′. Lower panel: velocity-resolved spectra of [C II] (colored in gray), ¹²CO J = 2−1 (blue), and ¹³CO J = 2−1 (cyan) in the direction of protrusion for the 12 selected positions in the upper panel. The vertical dotted red line at 9 km s⁻¹ marks the approximate velocity of the emission generated by the OMC and the associated star-forming molecular cloud behind the Veil.