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Paper: Global galactic distribution of 22Na
Volume: 261, The Physics of Cataclysmic Variables and Related Objects
Page: 633
Authors: Iyudin, A. F.
Abstract: Classical novae are believed to be the source of the ISM enrichment with the isotopes of 13C, 15N, 22Na and 26Al. The latter two, especially radioactive 22Na, that decays producing penetrating 1.275 MeV γ-ray photons, could be used as a check probe of the contemporaneous thermonuclear runaway theory (TNR) of classical novae. To tap this problem we have used a two-way approach, namely: (1) -- by attempting the 22Na line emission detection from old and more recent individual novae; and (2) -- by deriving the 22Na line emission global galactic distribution. Contrary to other wavelengths, in the γ-ray band the Galaxy is almost transparent, so that otherwise obscured bulge novae may be detectable up to Av ~103 in the γ-ray line emission. This makes possible to tap rather uncertain galactic novae rate by comparing observations of the individual galactic novae with the integrated 22Na line emission from the disk and/or bulge population. The accumulation of 22Na from the frequent novae in the bulge will lead to an observable extended emission. The COMPTEL telescope on board the Compton Gamma-Ray Observatory (CGRO), due to its combination of imaging and spectroscopic capabilities, is suitable to verify the above ideas. Our latest results on the global galactic distribution of the 1.275 MeV line emissivity clearly points to the asymmetric shape of the galactic bulge, as well, as to the enhanced rate of novae in the bulge.
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