Spectral fits to the OH 79 μm absorption lines in IRAS 17578–0400. The solid black histogram represents the data, the solid magenta line indicates the best multicomponent fit to the data, and the dashed blue lines are the individual components. The velocity scale is set relative to the frequency of the blue component of the doublet. The dashed vertical lines indicate the expected positions of the two absorption components given the adopted redshift of 0.0134.