Joint H.E.S.S. and Fermi-LAT analysis of the region around PSR J1813-1749

TL;DR

This study combines H.E.S.S. and Fermi-LAT data to analyze the complex gamma-ray emission around PSR J1813-1749, revealing extended emission and modeling its spectral properties across multiple wavelengths.

Contribution

It presents a joint analysis of H.E.S.S. and Fermi-LAT data, identifying extended gamma-ray emission and providing a continuous spectral model from GeV to TeV energies.

Findings

Detection of significantly extended gamma-ray emission coincident with HESS J1813-178.

A joint GeV-TeV spectral model describing the emission region.

Insights into hadronic or leptonic origins and diffusion parameters of the emission.

Abstract

HESS J1813-178 is one of the brightest sources detected during the first HESS Galactic Plane survey. The compact source, also detected by MAGIC, is believed to be a pulsar wind nebula powered by one of the most powerful pulsars known in the Galaxy, PSR J1813-1749 with a spin-down luminosity of $\dot{\mathrm{E}} = 5.6 \cdot 10^{37}\,\mathrm{erg}\,\mathrm{s}^{-1}$. With its extreme physical properties, as well as the pulsar's young age of 5.6 kyrs, the $\gamma$-rays detected in this region allow us to study the evolution of a highly atypical system. Previous studies of the region in the GeV energy range show emission extended beyond the size of the compact H.E.S.S. source. Using the archival H.E.S.S. data with improved background methods, we perform a detailed morphological and spectral analysis of the region. Additionally to the compact, bright emission component, we find significantly extended emission, whose position is coincident with HESS J1813-178. We reanalyse the region in GeV and derive a joint-model in order to find a continuous description of the emission in the region from GeV to TeV. Using the results derived in this analysis, as well as X-ray and radio data of the region, we perform multi-wavelength spectral modeling. Possible hadronic or leptonic origins of the $\gamma$-ray emission are investigated, and the diffusion parameters necessary to explain the extended emission are examined.