HESS Observations of the Galactic Center Region and Their Possible Dark Matter Interpretation

The detection of $\gamma$ rays from the source HESS J1745-290 in the Galactic Center (GC) region with the High Energy Spectroscopic System (HESS) array of Cherenkov telescopes in 2004 is presented. After subtraction of the diffuse $\gamma$-ray emission from the GC ridge, the source is compatible with a point source with spatial extent less than ${1.2}^{\prime }(\mathrm{stat})$ (95% C.L.). The measured energy spectrum above 160 GeV is compatible with a power law with photon index of $2.25\pm 0.04(\mathrm{stat})\pm 0.10(\mathrm{syst})$ and no significant flux variation is detected. It is finally found that the bulk of the very high energy emission must have non-dark-matter origin.