Integrated intensity of SO₂ 4_2,2 − 3_1,3 and 12_3,9 − 12_2,10, compared with CO and H₂CO emission near the protostar. All SO₂ transitions are integrated in the same velocity range as in Fig. 1. Crosses mark the locations of peaks 1 and 2. Top: SO₂ 4_2,2 − 3_1,3 integrated intensity map. Red and blue contours mark the same CO contours as in Fig. 1. Bottom: SO₂ 12_3,9 − 12_2,10 integrated intensity map. Blue contours represent the H₂CO integrated intensity, with contours drawn at 3,5 and 10 times the rms of the map (0.7 K km s⁻¹). The dashed line represents the direction of the PV diagram in Fig. 2.