PeV Photon and Neutrino Flares from Galactic Gamma-Ray Binaries

A M Bykov,S V Troitsky,A E Petrov,M E Kalyashova

doi:10.3847/2041-8213/ac2f3d

Abstract

Abstract The high-energy radiation from short period binaries containing a massive star with a compact relativistic companion was detected from radio to TeV γ-rays. We show here that PeV regime protons can be efficiently accelerated in the regions of collision of relativistic outflows of a compact object with stellar winds in these systems. The accelerated proton spectra in the presented Monte Carlo model have an upturn in the PeV regime and can provide very hard spectra of sub-PeV photons and neutrinos by photomeson processes in the stellar radiation field. The recent report of a possible sub-PeV γ-ray flare in coincidence with a high-energy neutrino can be understood in the frame of this model. The γ-ray binaries may contribute substantially to the Galactic component of the detected high-energy neutrino flux.

Highlights

The cosmic accelerators of petaelectronovolt (PeV) energy particles revealed themselves through the measured fluxes of the Galactic cosmic rays as well as by the high-energy neutrinos first detected by IceCube (Aartsen et al 2013; IceCube Collaboration 2013)
We show here that PeV regime protons can be efficiently accelerated in the regions of collision of relativistic outflows of a compact object with stellar winds in these systems
Recent modeling by Pittard et al (2021) of TeV regime particle acceleration in colliding wind binary with wind velocities ∼ few × 103 km s−1 and ∼ mG magnetic fields in the acceleration region demonstrated that ∼ 30% of the wind power was transferred to non-thermal particles

Summary

Introduction

The cosmic accelerators of petaelectronovolt (PeV) energy particles revealed themselves through the measured fluxes of the Galactic cosmic rays as well as by the high-energy neutrinos first detected by IceCube (Aartsen et al 2013; IceCube Collaboration 2013). The high-energy radiation from short period binaries containing a massive star with a compact relativistic companion was detected from radio to TeV gamma rays.

Results

Conclusion