CO(4−3) line-velocity integrated map (moment 0, left panel), line-of-sight velocity field (V_los, moment 1, central panel), and line-of-sight velocity dispersion field (σ_los, moment 2, right panel) of the quasar host–MQN01-QC galaxy system. These maps are obtained from the continuum-subtracted ALMA datacube using channels within [ − 700; +400] km s⁻¹ around the quasar systemic redshift (V_los = 0). The dotted (negative) and solid (positive) contours correspond to [ − 2, 3, 2n]σ, where n ≥ 2 is an integer, and σ denotes the noise RMS. The white crosses mark the peak emission of the 3 mm dust continuum. The 3σ contour of the 0th moment is also reported in the moment 1st and 2nd maps. The ALMA synthesized beam is shown in the bottom right corner.