A Search for Dark Matter Annihilation in the Milky Way Halo

Understand

The Milky Way halo is the brightest source of dark matter annihilation on the sky.

• Indeed, the potential strength of the Galactic dark matter signal can supersede that expected from dwarf galaxies and galaxy groups even in regions away from the Inner Galaxy.
• In this paper, we present the results of a search for dark matter annihilation in the smooth Milky Way halo for $|b| > 20^\circ$ and $r < 50^\circ$ using 413 weeks of Fermi Pass 8 data within the energy range of $\sim$0.8-50 GeV.
• We exclude thermal dark matter with mass below $\sim$70 GeV that annihilates to $b\bar{b}$ at the 95% confidence level using the p6v11 cosmic-ray foreground model, providing the strongest limits on the annihilation cross section in this mass range.