Spatially integrated, continuum-subtracted 2 mm spectra of G09v1.97 with a spectral resolution of 35 km s⁻¹. The vertical dotted lines represent the expected central positions of the lines. As argued in the text, that the weak emission at ∼745 GHz feature is likely dominated by the H₂O(2₁₁−2₀₂) line. The dot-dashed lines represent the corresponding Gaussian decompositions: blue represents the approaching gas component (marked as “B”) while orange and red represent the blue-shifted Gaussian component (marked as “Rb”) and red-shifted Gaussian component (marked as “Rr”) of the receding gas, respectively. The solid green line shows the sum. The average noise level of the spectra is ∼0.2 mJy with a spectral resolution of 50 km s⁻¹. Top: rest-frame 738–755 GHz spectrum combining SPW-0 and SPW-1. The light-blue shaded area indicates the 746–746.5 GHz gap between SPW-0 and SPW-1. The H₂O(2₁₁−2₀₂) line and the H₂O⁺(2₀₂−1₁₁)_(5/2−5/2) line are fitted with a single Gaussian profile due to limited S/N and the lack of data in the inter-band gap. Bottom: SPW-2 spectrum of CO(6–5). The dot-dashed and solid lines are the same as in the top panel. The left inset shows the fit of the spectrum using two Gaussian profiles (green lines). It is clear that a double-Gaussian profile does not fit well the total line profile of the source. It is because of this, we introduced a third Gaussian component in the fit. The right inset shows a comparison among the line profiles of CO(6–5), H₂O(2₁₁−2₀₂), and H₂O⁺(2₀₂−1₁₁)_(5/2−3/2). They are found to be similar, indicating a similar spatial distribution of the line-emitting regions.