[S II] 6716/6731 (bottom) and [S II] (6716 + 6731)/Hα and [N II] 6548/Hα (× 3.9) (top) obtained for the intrinsic emission as a function of relative distance. The filled dots correspond to points along slit position 1 and the red crosses correspond to points along slit position 2. The [N II] 6548/Hα (×  3.9) emission line ratios from the faint lobe (position 1) and from the “a2” to ”d2” features (position 2) are also shown in the top panel (as open circles). We have drawn a stright line in the bottom panel passing through the peak of the [S II] ratio of features “a2” to “d2” to illustrate the decrease of the [S II] line ratio from “a2” to “d2”.