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T: Fachverband Teilchenphysik

T 87: Gammaastronomie I

T 87.9: Talk

Monday, March 28, 2011, 18:50–19:05, 30.41: 104

Search for a DM annihilation signal from the Galactic Centre region with H.E.S.S — •Daniil Nekrassov, Christopher van Eldik, and Werner Hofmann — Max-Planck Institut für Kernphysik, Postfach 103980, 69029 Heidelberg

A search for a very-high-energy (VHE; ≥ 100 GeV) γ-ray signal from self-annihilating particle Dark Matter (DM) is performed towards a region of projected distance r∼ 45−150 pc from the Galactic Centre. At this distance, parametrisations of the galactic DM density profile like Navarro-Frenk-White (NFW) or Einasto density agree with each other within a factor of two, contrary to the very centre of the Galaxy, where the deviation can reach orders of magnitude. Thus, as opposed to γ-ray observations of dwarf galaxies or the very centre of the Milky Way, the results derived here do not depend strongly on the assumed DM profile. The background-subtracted γ-ray spectrum measured with the H.E.S.S. γ-ray instrument in the energy range between 300 GeV and 30 TeV shows no hint of a residual γ-ray flux, leading to upper limits on the velocity-averaged annihilation cross section ⟨σ v⟩ as a function of the DM particle mass, which are among the best reported so far for this energy range, especially if an Einasto-type DM profile is realized by nature.