On TeV Gamma Rays and the Search for Galactic Neutrinos

TL;DR

This paper explores the connection between TeV gamma rays and galactic neutrinos, analyzing Fermi data and discussing implications for astrophysical sources like Sgr A* and dark matter.

Contribution

It provides a detailed analysis of gamma-ray and neutrino fluxes from the Milky Way, constraining their relationship and implications for high-energy astrophysics.

Findings

Galactic contribution to IceCube neutrinos is likely small.

Gamma-ray flux constraints limit neutrino source models.

Sgr A* neutrino emissions may be gamma-ray suppressed due to opacity.

Abstract

The IceCube neutrino discovery presents an opportunity to answer long-standing questions in high-energy astrophysics. For their own sake and relations to other processes, it is important to understand neutrinos arising from the Milky Way, which should have an accompanying flux of gamma rays. Examining Fermi TeV data, and applying other constraints up to >1 PeV, it appears implausible that the Galactic fraction of the IceCube flux is large, though could be present at some level. We address Sgr A*, where the TeV-PeV neutrinos may outrun gamma rays due to gamma-gamma opacity, and further implications, including dark matter and cosmic-ray electrons.