Galactic 1.8 MeV Emission from Al-26

Abstract

The detection of the relatively short-lived (∼10⁶ yr) radioactive ²⁶ Al in our Galaxy, more than 12 years ago, convincingly showed that nucleosynthesis is still active today on a large scale. Still, despite considerable efforts in the past decade, the site of this nucleosynthetic activity cannot be identified from theory alone; several potential sites are still on the list, been able to provide the 2-3 M⊙ of ²⁶A1 per Myr, implied by the detected 1.8 MeV flux of ∼4 10⁻⁴ cm⁻² s⁻¹ from the galactic plane (see [7] for a review).