High energy gamma-radiation from the galactic center due to neutralino annihilation

Abstract We study the NGS (Non-dissipative Gravitational Singularity) model, which successfully describes the non-linear stage of evolution of perturbations (see Gurevich and Zybin, Sov. Phys. JETP 67 (1988) 1; Berezinsky; Gurevich and Zybin, Phys. Lett. B 294 (1992) 221; and references therein). This model predicts the DM density distribution ϱ ( r )∼ r − α with α⋍1.8 which holds from very small distances r min ⋍0.01 pc up to very large distances r max ⋍5 Mpc . Assuming the neutralino to be a CDM particle, we calculate the annihilation of neutralinos in the vicinity of the singularity (Galactic Center). If neutralinos are the dominant component of DM in our Galaxy, the produced energy is enough to provide the whole observed activity of the GC. Neutralinos of the most general composition and of mass in the range 20 GeV≲ m χ ≲1 TeV are considered. We find the neutralino compositions which give the relic density needed for the Mixed Dark Matter (MDM) model and we evaluate for these compositions the high-energy ( E γ >100 Mev ) gamma-ray flux under the constraint that the radio flux is lower than the observational limit. The compositions with the detectable gamma-ray flux which we found are provided by a set of almost pure gaugino states with the neutralino mass between 100 and 500 GeV. We demonstrate that a detectable high-energy gamma-ray flux is produced by the neutralino annihilation also in the case when neutralinos provide a small fraction (down to 0.1%) of the DM in our Galaxy. The predicted flux is F γ ∼ 10 −7 −10 −8 cm −2 s −1 for E γ ≳300 MeV