Understanding the extreme pulsar wind nebula HESSJ1825-137 and surrounds

HESSJ1825-137 is one of the most powerful and luminous TeV gamma-ray pulsar wind nebulae (PWN) with known supernova remnant (SNR) rims. To the south of HESSJ1825-137, data from the space-based gamma ray observatory Fermi-LAT revealed a new region of GeV gamma ray emission. Cosmic rays may be accelerated by HESSJ1825-137 (or its projenitor SNR) to high energies that escape into this new region to interact with the interstellar medium (ISM) to form the observed GeV gamma rays. This study presents new ISM analysis and modelling of the spectral energy distribution towards the GeV gamma radiation (from hadronic and leptonic components) and to determine whether HESSJ1825-137 or another local accelerator is a plausible source of the required high energy particles.