Diffuse Ultra-High-Energy Gamma-Ray Emission From TeV Halos

TL;DR

This paper demonstrates that the diffuse ultra-high-energy gamma-ray emission observed from the Galactic Plane is primarily due to TeV halos around pulsars, which convert a significant fraction of their spin-down power into gamma rays.

Contribution

It provides observational evidence linking TeV halos to the diffuse gamma-ray emission at energies up to 1 PeV, supporting their dominant role in the ultra-high-energy sky.

Findings

Diffuse gamma-ray emission matches TeV halo predictions

TeV halos convert about 5% of pulsar spin-down power into gamma rays

TeV halos likely dominate the ultra-high-energy gamma-ray sky

Abstract

The LHAASO Collaboration has recently reported a measurement of the diffuse gamma-ray emission from the Galactic Plane at energies between 10 TeV and 1 PeV. While this emission is brighter than that expected from cosmic-ray interactions in the interstellar medium alone, we show that the intensity, spectrum, and morphology of this excess are in good agreement with that predicted from the "TeV halos" which surround the Milky Way's pulsar population. These results support the conclusion that TeV halos dominate the ultra-high-energy sky, and that these objects convert $\sim 5\%$ of their total spindown power into very-high and ultra-high-energy photons.