Constraints on the Origins of the Galactic Neutrino Flux Detected by IceCube

Abstract

Galactic and extragalactic objects in the Universe are sources of high-energy neutrinos that may contribute to the astrophysical neutrino signal seen by IceCube. Recently, a study done using cascade-like events seen by IceCube reported neutrino emission from the Galactic plane with >4 σ significance. In this work, we put a lower limit on the number of Galactic sources required to explain this emission. To achieve this, we use a simulation package created to simulate point sources in the Galaxy along with the neutrino and gamma-ray flux emissions originating from them. Along with using past IceCube discovery potential curves, we also account for Eddington bias effects due to Poisson fluctuations in the number of detected neutrino events. We present a toy Monte Carlo simulation to show that there must be at least eight sources, each with luminosity less than 1.6 × 10 ^35 erg s ^−1 , responsible for the Galactic neutrino emission. Our results constrain the number of individual point-like emission regions, which apply both to discrete astrophysical sources and to individual points of diffuse emission.

Keywords

• Neutrino astronomy
• High energy astrophysics
• the Milky Way
• Astronomical simulations