Position-velocity diagrams of the gas physical conditions in the jet (a histogram equivalent colour scale is used). The electron density, n_e, in units of 10⁴ cm^-3 (top left), the ionisation fraction, x_e(top right), the temperature, T_e, in units of 10⁴ K (bottom right), and the total density, n_H, in units of 10⁴ cm^-3 (bottom left) are calculated for each pixel of the spectral images. (1 pix=0.378′′ in the spatial direction and 2.15 km s^-1 in the spectral direction; angular resolution: FWHM_seeing ~ 0.8′′ ~ 2 pixels, spectral resolution: FWHM_inst ~ 8.8 km s^-1 ~ 4 pixels). The errors on the estimated values of n_e, x_e, T_e, n_H may vary between a few percent and 50% depending on the line signal-to-noise on each pixel.