Global Galactic distribution of the 1.275 MeV γ-ray line emission
Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, 85741 Garching, Germany e-mail: email@example.com
2 Research and Scientific Support Division, ESTEC, 2200 AG Noordwijk, The Netherlands
3 University of New Hampshire, Institute for Studies of Earth, Oceans and Space, Durham NH 03284, USA
Accepted: 22 July 2005
We present results of the analysis of 1.275 MeV γ-ray line global distribution derived from the all-sky data accumulated by COMPTEL on board the Compton Gamma Ray Observatory (CGRO) from 1991 to 1997. Previously the 1.275 MeV γ-ray line was believed to be largely produced in the decay of radioactive isotope 22Na that is synthesised in the classical nova (CN) thermonuclear runaway (TNR). Another way to produce the 1.275 MeV line emission is via the excitation of 22Ne-nuclei, e.g. through the low-energy cosmic ray interactions with the nuclei of the interstellar matter that lead to the production of 22Ne*, or of 22Na. This scenario, as we now believe, can be dominant in contributing to the total 1.275 MeV γ-ray line emission from the galactic bulge. Unfortunately, systematic uncertainties in the analysis of the COMPTEL data hinder a clear distinction between two alternative scenarios.
Key words: gamma-rays: observations / Galaxy: abundances / Galaxy: bulge / ISM: abundances / ISM: cosmic rays / nuclear reactions, nucleosynthesis, abundances
© ESO, 2005