Emission of SO, SiS, and SO₂ integrated in velocity. Upper panels: velocity-integrated emission of, from left to right, SO N = 3−2, N = 2−1(2), N = 2−1(3), and N = 4−4 (see Table 1 for the spectral parameters). The integration velocity range is 85.7–105.8 km s⁻¹ in all images to match the velocity interval where the PN emission is detected. The black contours start from the 3σ rms level of the integrated maps, which is, from left to right: 4.8 × 10⁻² Jy beam⁻¹ km s⁻¹; 2.5 × 10⁻² Jy beam⁻¹ kms⁻¹; 3.6 × 10⁻² Jy beam⁻¹ kms⁻¹; 2.7 × 10⁻² Jy beam⁻¹ km s⁻¹, and the step is of 10σ rms. The white contour corresponds to the PN integrated emission, and the numbered regions 1 and 2 are those defined in Fig. 1. The synthesised beam is illustrated in the lower-left corner. To the right of the quantum numbers, we indicate the E_up of the transition. Lower panels: same as the upper panels for the SiS J = 5−4 and J = 6−5 lines, and the and lines. The 3σ rms level is: 2.9 × 10⁻² Jy beam⁻¹ km s⁻¹ for SiS J = 5−4; 2.3 × 10⁻² Jy beam⁻¹ km s⁻¹ for SiS J = 6−5; 2.95 × 10⁻³ Jy beam⁻¹ km s⁻¹ for Jy beam⁻¹ km s⁻¹ for .