C. Farnier

Direct constraints on minimal supersymmetry from Fermi-LAT observations of the dwarf galaxy Segue 1

The dwarf galaxy Segue 1 is one of the most promising targets for the indirect detection of dark matter. Here we examine what constraints 9 months of Fermi-LAT gamma-ray observations of Segue 1 place upon the Constrained Minimal Supersymmetric Standard Model (CMSSM), with the lightest neutralino as the dark matter particle. We use nested sampling to explore the CMSSM parameter space, simultaneously fitting other relevant constraints from accelerator bounds, the relic density, electroweak precision observables, the anomalous magnetic moment of the muon and B-physics. We include spectral and spatial fits to the Fermi observations, a full treatment of the instrumental response and its related uncertainty, and detailed background models. We also perform an extrapolation to 5 years of observations, assuming no signal is observed from Segue 1 in that time. Results marginally disfavour models with low neutralino masses and high annihilation cross-sections. Virtually all of these models are however already disfavoured by existing experimental or relic density constraints.

Search for Gamma-ray Line Signatures with H.E.S.S

Many results from astrophysical observations point to a 27% contribution of non-baryonic dark matter to the mass-energy budget of the universe. Although still elusive, strongly motivated candidates in form of weakly interacting massive particles could explain the nature of dark matter, and their annihilation or decay would give rise to detectable signatures in gamma-rays. In 2012, the H.E.S.S. collaboration started taking data with the largest imaging atmospheric Cherenkov telescope in the world which significantly lowered the energy threshold of the already operational four-telescope system. In particular, due to its location and improved performance at low energies, the H.E.S.S. experiment is now in a position to extend the search for dark matter line signals down to the 100 GeV mass range. The sensitivity to line searches with a new full likelihood approach will be discussed and preliminary results from observations with the second phase of H.E.S.S. will be presented.