Best fit of the LVG model for CO lines in knot A considering two components. The parameters of the first component (dotted line) are: N(CO)= 6 × 10¹⁶ cm^-2, size = 24′′, T = 70 K, n(H₂) = 4 × 10⁶ cm^-3: they are the physical parameters of the low excitation gas component averaged inside the 24′′  beam centred towards the knot A position; this component is, however, more extended than the beam. The parameters of the second component (dashed line) are: N(CO)= 3 × 10¹⁵ cm^-2, size = 18′′, T = 2200 K, n(H₂) = 4 × 10⁴ cm^-3. The solid line represents the sum of the two components.