Flux versus wavelength of all the counterpart candidates found for core D a) and core N b). Dots of different colours represent different counterpart candidates that have the same spatial position (after taking pointing errors into consideration). The distance of the counterpart candidates to the nominal position of the submillimetre cores is given by the size of the black circle that surrounds each coloured dot. At the right bottom of each figure a) and b), a diagram with the equivalence between the black circle radius and the distance to the cores is indicated. For Core D, the closest counterpart candidate has an SED typical of a YSO, while the rest of the sources located at other more distant positions show no clear nature. In Core N, no YSO is associated and only a source with an SED typical of an extinct background star (black dots; and hence not associated with the submillimetre core) is found.