Speaker
Description
Cosmological N-body simulations show that Milky-Way-sized galaxies harbor a population of unmerged dark matter subhalos. These subhalos could shine in gamma rays and be eventually detected in gamma-ray surveys as unidentified sources. We search for very-high-energy (VHE, E ≥ 100 GeV) gamma-ray emission using H.E.S.S. observations carried out on a thorough selection of unidentified Fermi-LAT Objects (UFOs) as dark matter subhalo candidates. Provided that the dark matter mass is higher than a few hundred GeV, the emission of the UFOs can be well described by dark matter annihilation models. No significant VHE gamma-ray emission is detected in any UFO dataset nor in their combination. We, therefore, derive constraints on the product of the velocity-weighted annihilation cross-section <sigma v> by the J-factor on dark matter models describing the UFO emissions. Upper limits at 95% confidence level (CL) are derived on sigma v J in W+W- and \tau+\tau- annihilation channels for the TeV dark matter particles. Focusing on thermal WIMPs, strong constraints on the J-factors are obtained from H.E.S.S. observations. Adopting model-dependent predictions from cosmological N-body simulations on the J-factor distribution function for Milky Way-sized galaxies, the dark matter models for the UFO emissions could be ruled out at high confidence level.
Keywords
Dark Matter, Gamma-ray sources, Dark matter subhalos
| Subcategory | Experimental Results |
|---|---|
| Collaboration | H.E.S.S. |
