The TeV gamma-ray luminosity of the Milky-Way and the contribution of H.E.S.S. unresolved sources to VHE diffuse emission

TL;DR

This paper analyzes H.E.S.S. survey data to estimate the Milky Way's TeV gamma-ray luminosity and assesses how unresolved sources contribute to diffuse emission, providing insights into the Galactic TeV source population and pulsar activity.

Contribution

It provides the first comprehensive estimate of the Milky Way's TeV gamma-ray luminosity and quantifies the contribution of unresolved sources to diffuse emission, linking it to pulsar populations.

Findings

Milky Way's TeV luminosity is approximately 1.7 x 10^{37} erg/sec.

Unresolved sources significantly contribute to the diffuse TeV emission.

Most bright sources are likely powered by pulsar activity.

Abstract

H.E.S.S. has recently completed a systematic survey of the Galactic plane in the TeV energy domain. We analyze the flux, latitude and longitude distributions of $\gamma-$ray sources observed by H.E.S.S. in order to infer the properties of Galactic TeV source population. We show that the total Milky-Way luminosity in the 1-100 TeV energy range is $L_{\rm MW} = 1.7^{+0.5}_{-0.4}\times 10^{37} {\rm ergs}\,{\rm sec}^{-1}$. Evaluating the cumulative flux expected at Earth by the considered population, we show that H.E.S.S. unresolved sources provide a relevant contribution to the diffuse Galactic emission. Finally, in the hypothesis that the majority of bright sources detected by H.E.S.S. are powered by pulsar activity, like e.g. Pulsar Wind Nebulae or TeV halos, we estimate the main properties of the pulsar population.