Line profiles of some emission lines as compared with two low-excitation H₂O ν₂ = 1 − 0 absorption lines. The velocity scale on the abscissa is calculated with a redshift of z = 0.08778. All mid-IR molecular absorption lines have peak absorption blueshifted by 100 − 200 km s⁻¹ relative to the peak emission lines, as exemplified by the H₂O lines. Note that the rotational CO 2-1 line shows absorption below the continuum at velocities from −350 to −570 km s⁻¹ as highlighted in the insert, consistent with the H₂O wing absorption at similar velocities.