Observational and simulated H₂O and HO line profiles. Left panel: observational spectra (black histograms) of four and two transitions of H₂O and HO, respectively, for the CND₁ position. The modeled water line profiles obtained using a two-component model are shown with red histograms. We also show the ¹³CO(10-9) line profile. Central panel: observational spectra (black histograms) of four and two transitions of H₂O and HO, respectively, for the CND₂ position. The modeled water line profiles obtained using a two-component model are shown with red histograms. Line profiles of ¹³CO(10–9) and CS(11–10) are also shown, but the CS(11–10) line (near the HO(1₁₀–1₀₁) line) appears as a consequence of the HIFI double sideband. Right panel: observational spectra (black histograms) of four and two transitions of H₂O and HO, respectively, for the 20 km s⁻¹ cloud position. The modeled water line profiles are shown with red histograms. Spectral features of ¹³ CO(10–9), C¹⁸ O(5–4), ¹³ CO(5–4), CH₃OH(5₁₅ − 4₀₄), CH(1_−1,2 − 1_1,1), and HCO⁺(6–5) are also shown, with the last three lines coming from the HIFI double sideband. The HO(1₁₀–1₀₁) line is blended with the ¹³CH₃OH(1₆₂–1₆₁) line (this line also is due to the HIFI double sideband).