Revealing a new region of gamma-ray emission in the vicinity of HESS J1825-137. (arXiv:1902.07813v1 [astro-ph.HE])

Revealing a new region of gamma-ray emission in the vicinity of HESS J1825-137. (arXiv:1902.07813v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Araya_M/0/1/0/all/0/1">M. Araya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mitchell_A/0/1/0/all/0/1">A.M.W. Mitchell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parsons_R/0/1/0/all/0/1">R.D. Parsons</a>

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.

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