Galactic 1.275 MeV emission from ONe novae and its detectability by INTEGRAL/SPI

Abstract

Models of Galactic 1.275 MeV emission produced by the decay of the radionuclide $^{22}$Na have been computed. Several frequency-spatial distributions of novae have been investigated using recent results of nova rates and spatial distributions of novae in our Galaxy. These models allow us to estimate the lower-limit of the $^{22}$Na mass ejected per ONe nova detectable with the future spectrometer (SPI) of the INTEGRAL observatory as a function of the frequency-spatial distribution of ONe novae in the Galaxy. Calculations using recent estimations of the expected $^{22}$Na mass ejected per ONe nova show that the detection of the Galactic emission of 1.275 MeV photons will be difficult with the future spectrometer of the INTEGRAL observatory, whereas the cumulative emission around the Galactic center has some chances to be detected during the deep survey of the central radian of the Galaxy.

12 pages, 17 figures, MNRAS in press