6533b824fe1ef96bd1280cc0
RESEARCH PRODUCT
Conservative upper limits on WIMP annihilation cross section from Fermi-LAT $γ$-rays
V. De RomeriFiorenza DonatoF. Caloresubject
HistoryAstrophysics::High Energy Astrophysical PhenomenaDark matterAstrophysicsAstrophysics::Cosmology and Extragalactic Astrophysics01 natural sciencesEducationlaw.inventionGalactic haloTelescopeCross section (physics)WIMPlaw0103 physical sciences010306 general physicsAstrophysics::Galaxy AstrophysicsPhysicsastro-ph.HEAnnihilation010308 nuclear & particles physicsIsotropyhep-phComputer Science ApplicationsHigh Energy Physics - PhenomenologyAstrophysics - High Energy Astrophysical PhenomenaAstrophysics - Cosmology and Nongalactic AstrophysicsFermi Gamma-ray Space Telescopedescription
The spectrum of an isotropic extragalactic {\gamma}-ray background (EGB) has been measured by the Fermi-LAT telescope at high latitudes. Two new models for the EGB are derived from the subraction of unresolved point sources and extragalactic diffuse processes, which could explain from 30% to 70% of the Fermi-LAT EGB. Within the hypothesis that the two residual EGBs are entirely due to the annihilation of dark matter (DM) particles in the Galactic halo, we obtain stringent upper limits on their annihilation cross section. Severe bounds on a possible Sommerfeld enhancement of the annihilation cross section are set as well. Finally, we consider models for DM annihilation depending on the inverse of the velocity and associate the EGBs to photons arising from the annihilation of DM in primordial halos. For DM velocities in protohalos of v ~ 10^-8 c, the annihilation cross section is constrained down to 10^-33 cm^3 /s for DM masses below 100 GeV. Given our choices for the EGB and the minimal DM modelling, the derived upper bounds are claimed to be conservative.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2011-05-21 |