Comparison of the averaged spectra of the SO and H₂CO lines with the HCO⁺3→2 line profile. In the top of these panels we have the HCO⁺3→2 profile showing the double-peak shape that is characteristic of a rotating disk. In the middle we can see the averaged H₂CO profile that keep the same double-peak feature in the same range of velocities. In the bottom the averaged SO profile is in complete agreement with the two other spectra.