Estimating the contribution of Galactic sources to the diffuse neutrino flux

TL;DR

This paper investigates whether microquasars, especially LS 5039, can significantly contribute to the diffuse high-energy neutrino flux observed by IceCube, by modeling proton acceleration and interactions in these sources.

Contribution

It demonstrates that high-mass X-ray binary microquasars could be major sources of the diffuse neutrino flux, based on maximum parameter assumptions and population distribution.

Findings

LS 5039 can accelerate protons above 20 PeV.

Microquasars could dominate the diffuse neutrino flux.

Spatial distribution supports their significant contribution.

Abstract

Motivated by recent IceCube observations we re-examine the idea that microquasars are high energy neutrino emitters. By stretching to the maximum the parameters of the Fermi engine we show that the nearby high-mass X-ray binary LS 5039 could accelerate protons up to above about 20 PeV. These highly relativistic protons could subsequently interact with the plasma producing neutrinos up to the maximum observed energies. After that we adopt the spatial density distribution of high-mass X-ray binaries obtained from the deep INTEGRAL Galactic plane survey and we assume LS 5039 typifies the microquasar population to demonstrate that these powerful compact sources could provide a dominant contribution to the diffuse neutrino flux recently observed by IceCube.