Assessment of tracers of 1.8 MeV emission

COMPTEL 1.8 MeV gamma-ray line data have been compared to an extended set o f all-sky maps, covering the entire explored wavelength range from the radi o band up to high-energy gamma-rays. This analysis revealed that tracers of the old stellar population provide only a poor description of the data. Tr acers of the young stellar population considerably improve the fit. Residua ls are minimised for the free-free emission map obtained by the DMR at micr owave wavelengths and the 158 mu m fine-structure line map of C+ observed b y FIRAS. Within the statistics of the present data, both maps provide an ov erall satisfactory fit. We therefore conclude that adequate tracers of Al-2 6 sources have now been identified.