C1 clump and surroundings. The sources discussed in the text are identified. a) Colour image with the 5.8 μm, 4.5 μm, and 3.6 μm emissions in red, green, and blue, respectively (logarithmic units). The red contours refer to the column density (levels of 0.3, 0.5, 0.75, 1.0, 1.5, and 2 × 10²³ cm^-2). b) Colour image with the 70 μm, 8.0 μm, and 3.6 μm emissions in red, green, and blue, respectively (linear units). c) MIPSGAL image at 24 μm; the contours are for the 70 μm emission (levels at 5000, 10 000, 15 000, and 20 000 MJy/sr). A, B, and C are slightly extended sources of 8.0 μm, 24 μm, and 70 μm emission. d)Herschel 70 μm image.