COMPTEL spectral study of the inner galaxy

We present first steps towards fine-resolution COMPTEL spectra of the galactic γ-ray glow at 0.75–30 MeV, combining all data from the first 5 years of the mission. The spectra are not fully deconvolved yet. We show that there is evidence for deviations from a smooth continuum spectrum in the inner-Galaxy emission. Two broad spectral excesses seem to be present, namely below the 26Al 1.8 MeV line down to ∼1.3 MeV and at 3–7 MeV, each containing a flux of the order 10−4 γ cm−2 s−1 rad−1. We find that the excess emission appears to have a rather wide latitude distribution. The spectral features suggest the presence of nuclear deexcitation lines as a possible explanation.