# Revealing a new region of gamma-ray emission in the vicinity of HESS J1825-137

## TL;DR

This paper reports the discovery of a new gamma-ray emission region near HESS J1825-137, suggesting a possible link to the supernova remnant and providing insights into particle acceleration processes.

## Contribution

The study presents the first detection of gamma-ray emission beyond the PWN, indicating a potential association with the SNR and expanding understanding of gamma-ray sources.

## Key findings

- Detected gamma-ray emission beyond the PWN region
- Spectral analysis shows a hard photon index of ~1.9
- Discussion of scenarios including SNR origin and lepton leakage

## Abstract

HESS J1825-137 is a bright very-high-energy (VHE) gamma-ray source that has been firmly established as a pulsar wind nebula (PWN), and one of the most extended gamma-ray objects within this category. The progenitor supernova remnant (SNR) for this PWN has not been firmly established. We carried out an analysis of gamma-ray observations in the region of HESS J1825-137 with the Fermi-LAT which reveal emission in the direction away from the Galactic plane. The region lies beyond the PWN and reaches a distance from the pulsar compatible with the supposed location of the SNR shock front. The spectrum of the gamma-rays is hard with a photon index of $\sim 1.9$ in the 10-250 GeV range. Several scenarios for the origin of the emission are discussed, including the SNR as a source of high-energy particles and the "leakage"' of leptons from the PWN.