Positron excess in the center of the Milky Way from short-lived $\beta^+$ emitting isotopes

摘要

Observations of the INTEGRAL satellite revealed the presence of yetunexplained excess in the central region of the Galaxy at the energies around511 keV. These gamma-rays are produced in the process of positron annihilation,the needed rate is around $10^{42}~\mathrm{s^{-1}}$. In this short paper it isshown that \pos -emitting isotopes that are formed in interactions ofsubrelativistic cosmic rays (CRs) with light nuclei (CNONe) can account for aconsiderable fraction -- up to several tens of percent -- of $e^{+}$ productionrate in the central region.