Isolated absorption features from each of our data sets showing line width comparisons. The best-fit model is plotted in red. Note that the b = 3.20 km s⁻¹ used for SO₂ here is an upper limit for the intrinsic line width. For the best-fit parameters and their definitions, see Section 3.1. Panels (a) and (b) are isolated absorption features from the SO₂ and ¹³CO spectra, respectively. Panels (c) and (d) are of the same SO₂ absorption feature, one convolved to the same resolution as our ¹³CO data. The point with error bars represents the typical uncertainty for the observed spectra in that panel.