Seeing through the haze: Constraining dark-matter annihilation in the presence of astrophysical point sources - Ben Safdi, MIT

Wed, Dec 9, 2015, 3:30 pm to 4:30 pm
Jadwin A06
Dark matter (DM) annihilating in the Milky Way and beyond may give rise to unique astrophysical signatures. However, these potential signs of new physics are easily confused with standard but poorly understood astrophysical backgrounds, such as populations of dim point sources like millisecond pulsars. I will present a new method to characterize unresolved astrophysical point sources (PSs), generalizing traditional template fits to account for non-Poissonian photon statistics. I will apply this method to Fermi gamma-ray data to characterize PS populations in the Inner Galaxy and at high Galactic latitudes. In in the Inner Galaxy, I will provide evidence for a new point-source population distributed consistently with the observed ~GeV gamma-ray excess. The excess is fully absorbed by such a population, in preference to DM annihilation. The inferred source population is dominated by near-threshold sources, which may be detectable in future searches. I will comment on ongoing work to identify members of this new source population using gamma ray data along with input from other wavelengths. At high Galactic latitudes, I will show that accounting for unresolved flux from active galactic nuclei and star-forming galaxies allows us to significantly improve upon limits of extra-galactic DM annihilation. I will conclude by commenting on how these results may help understand the origin of the ultra-high-energy neutrino flux observed by the IceCube experiment.