Probing the Galactic origin of the IceCube excess with gamma rays

The IceCube Collaboration has recently reported evidence for a high-energy extraterrestrial neutrino flux. During two years of operation 28 events with energies between 30 TeV and 1.2 PeV were observed while only 10.6 events were expected from conventional atmospheric backgrounds. The hadronic interactions responsible for this IceCube excess will also produce a flux of high-energy γ-rays that can serve as a probe of source direction and distance. We show that existing TeV to PeV diffuse γ-ray limits support the interpretation that the IceCube excess is mostly of extragalactic origin. However, we point out that γ-ray surveys are biased in the Northern Hemisphere whereas the recent IceCube data tentatively show a weak preference for the Southern Sky. Possible sub-dominant contributions from Galactic neutrino sources like remnants of supernovae and hypernovae are marginally consistent with present γ-ray limits. This emphasizes the importance of future diffuse TeV to PeV γ-ray surveys in the Southern Hemisphere, particularly in the extended region around the Galactic center including the Fermi Bubbles.