Emission lines detected with NOEMA (black histograms) and Gaussian fits (total: red lines; if two components are present, individual components are displayed in blue colour). The velocity resolution is 68 km s⁻¹ in all cases. The labels in the top right corners indicate if the spectra were extracted from the integrated emission (“Integrated”, top panels), from the central pixel (bottom panels), or in the case of HOC⁺, from the pixel at (0ʺ̣2, −0ʺ̣05).