CO(3–2) spectrum extracted using 120 km s⁻¹ bins within a circle of 4″ diameter, i.e., an aperture as large as the synthesised beam of our NOEMA observations (top). The spectrum extracted at pixel (−0.78, −7.85″) is also shown, shifted by −1 mJy for convenience. The zero of the velocity scale corresponds to the systemic redshift z = 2.631 inferred from the narrow [O III] emission (Noterdaeme et al. 2021).