Gamma Rays From Dark Matter Subhalos Revisited: Refining the Predictions and Constraints

Understand

Utilizing data from the ELVIS and Via Lactea-II simulations, we characterize the local dark matter subhalo population, and use this information to refine the predictions for the gamma-ray fluxes arising from annihilating dark matter in this class of objects.

• We find that the shapes of nearby subhalos are significantly altered by tidal effects, and are generally not well described by NFW density profiles, instead prefering power-law profiles with an exponential cutoff.
• From the subhalo candidates detected by the Fermi Gamma-Ray Space Telescope, we place limits on the dark matter annihilation cross section that are only modestly weaker than those based on observations of dwarf galaxies.
• We also calculate the fraction of observable subhalos that are predicted to be spatially extended at a level potentially discernible to Fermi.