H₂O ﹩{10}_{\mathrm{2,9}}﹩–9﹩{}_{\mathrm{3,6}}﹩ spectrum toward HL Tau (red) and co-added ¹³CO v = 1–0 (4.7 μm) line emission (blue) toward the same source (Herczeg et al. 2011). The calibrator spectrum of 3c120 is shown for comparison (cyan). Gaussians are fitted to the HL Tau line profiles (cyan), and the baselines are shown (green); the source velocity is marked in magenta. The ¹³CO spectrum has been offset for clarity, the units are arbitrary for this spectrum, and the deep envelope self-absorption is masked out. The H₂O spectra for both HL Tau and 3c120 are obtained over the same region where emission >3σ and r < 5″ (Figure 1).The data used to create this figure are available.