Left: the Spitzer-IRAC map of band 2 at 4.5 μm (grey scale) is compared with the SiO(5−4) map integrated in the blue- (−20, +5 km s^-1, cyan contours) and red-shifted (+10, +55 km s^-1, red contours) velocity ranges. Offsets are with respect to IRAS4A1. The contour levels of emission are traced at 5 and 8σ levels and increase in steps of 5σ, where σ = 100 mJy beam^-1 for the red-shifted emission and 70 mJy beam^-1 for the blue-shifted emission. Negative emission is shown with dashed contours starting at the 3σ level and decreasing in steps of 3σ. The positions of the continuum sources at 1.3 mm are marked in green. The PdBI synthesised beam (HPBW) is shown in the bottom-left corner. Middle and right: same as the left panel for the SO(6₅−5₄) and ¹²CO(2−1) emissions, respectively. The rms noise of the velocity-integrated maps are: σ = 110 mJy beam^-1 and 90 mJy beam^-1 for the red- and blue-shifted SO(6₅−5₄) emissions, respectively; and σ = 500 mJy beam^-1 and 400 mJy beam^-1 for the red- and blue-shifted ¹²CO(2−1) emissions, respectively.