Gamma-Ray Line Signals from [TSUP]26[/TSUP]A[CLC]l[/CLC] and [TSUP]60[/TSUP]F[CLC]e[/CLC] in the Galaxies of the Local Group

Open Access
Publisher Website
Google Scholar
Abstract
Steady state γ-line fluxes from the decay of 26Al and 60Fe situated in the Local Group galaxies LMC, SMC, NGC 6822, IC 1613, M31, and M33 are estimated with standard supernova yields and supernova rates based on blue luminosities and other indicators of massive star formation. The largest 26Al flux, 2.0 × 10-6 γ s-1 cm-2, comes from the LMC, while the SMC is estimated to provide an 26Al flux of 3.6 × 10-7 γ s-1 cm-2. Andromeda is surprisingly weak, only about 1.6 × 10-8 γ s-1 cm-2 because of both its distance and its current low rate of star formation. Expected 60Fe fluxes are about 16% of the 26Al flux. Detection of these fluxes is feasible but will probably require sensitivities greater than those of the International Gamma-Ray Astrophysical Laboratory mission. The chief utility of such observations is the new insight they provide into the mechanisms of supernova explosions, the distribution and nature of massive-star-forming regions in irregular and spiral galaxies, and the nucleosynthetic history of Local Group members.