Left panel: 870 μm continuum emission map. Dust clumps are indicated. The grayscale goes from −0.1 to 2.0 Jy beam^-1. Contour levels correspond to 0.2, 0.35, 0.5, and 0.7 Jy beam^-1, and from 0.75 to 2.0 Jy beam^-1 in steps of 0.25 Jy beam^-1. The large square indicates the region observed in CO lines and the different symbols have the same meaning as in Fig. 6. Right panel: overlay of the emission at 870 μm (grayscale) and the CO contours of Fig. 6. IR sources listed in Table 3 are indicated.