Baseline subtracted CO(4→3) spectra for the total emitting region (a), the northern component (b), the southern component (c), and the QSO (d). For the N and S components, we chose as regions of integration those denoted by the ellipses in Fig. A.1b, while for the QSO we chose a 1″ × 1″ region centered around it that corresponds fairly well to the extent of the continuum emission (Fig. A.1d). In panels (a), (b), and (c) the solid line shows the Gaussian best fit to the CO(4→3) line. Velocities, shown on the x axis, are evaluated with respect to the NLR redshift. The BLR is blueshifted to a velocity of -2035.7 km s⁻¹.