Constraints on the Diffuse Gamma-Ray Background with HAWC
Abstract
The Diffuse Gamma-Ray Background (DGB) above 100 GeV is high-latitude emission expected to be produced by unresolved extragalactic objects such as active galactic nuclei, isotropic Galactic gamma-rays, and possible emission from dark matter annihilations or decays in the Galactic dark matter halo. The DGB has been observed up to nearly 1 TeV, but has yet to be detected at higher energies. Detections or stringent limits on the DGB above this energy would have strong multimessenger consequences, such as constraining the origin of astrophysical neutrinos observed in IceCube. The High Altitude Water Cherenkov (HAWC) observatory observes gamma rays above 100 GeV and continuously observes the sky, observing over 2/3 of the sky each day. With its high energy reach and large areal coverage, HAWC can search for the DGB at energies above 1 TeV. In order to isolate gamma-ray air showers from background hadronic showers, we will use topological cuts on HAWC air showers to create a dataset dominated by gamma-ray-like emission. In addition, due to its nearly-isotropic nature, the search for DGB emission requires non-standard background estimation methods for HAWC. We will present a limit on the DGB with HAWC as well as its implications for multimessenger and dark matter studies.
- Publication:
-
APS April Meeting Abstracts
- Pub Date:
- 2019
- Bibcode:
- 2019APS..APRQ08002H