De-excitation C and O lines and the 511 keV annihilation line from Sgr A

Abstract : We present a model of the observed annihilation emission from the Galactic center. From our estimations it follows that this region should emit also a flux of de-excitation C and 0 lines at the level <= 10(-5) ph cm(-2) s(-1). From restrictions based on the observed >100 MeV gamma-ray flux from the Galactic center, similar to 2 x 10(-s) ph cm(-2) s(-1), we predict that the calculated gamma-ray line flux below 8 MeV is about 2.5 x 10(-5) ph cm(-2) s(-1). A specific line is the one at 1.809 MeV from radioactivity of Al-26 The predicted quasi-stationary flux of the Al-26 1.809 MeV line from the 1 degrees x 1 degrees central region is <= 10(-6) ph cm(-2) s(-1). (C) 2008 Elsevier B.V. All rights reserved.