Morphology and hardness ratio exploitation under limited statistics

TL;DR

This paper explores advanced methods to analyze gamma-ray sky maps with limited photon data, aiming to better distinguish emission mechanisms like leptonic and hadronic processes in very high energy astrophysics.

Contribution

It introduces novel analytical tools to improve the interpretation of gamma-ray data under low-statistics conditions, enhancing the ability to differentiate emission origins.

Findings

Improved spatial feature significance estimation.

Enhanced spectrum extraction techniques.

Better discrimination between leptonic and hadronic emissions.

Abstract

Gamma-ray astronomy has produced for several years now sky maps for low photon statistics, non-negligible background and comparatively poor angular resolution. Quantifying the significance of spatial features remains difficult. Besides, spectrum extraction requires regions with large statistics while maps in energy bands allow only qualitative interpretation. The two main competing mechanisms in the VHE domain are the Inverse-Compton emission from accelerated electrons radiating through synchrotron in the X-ray domain and the interactions between accelerated hadrons and the surrounding medium, leading to the production and subsequent decay of Pi0 mesons. The spectrum of the VHE emission from leptons is predicted to steepen with increasing distance from the acceleration zone, owing to synchrotron losses (i.e. cooled population). It would remain approximately constant for hadrons. Ideally, spectro-imaging analysis would have the same spatial scale in the TeV and X-ray domains, to distinguish the local emission mechanisms. More realistically, we investigate here the possibility of improving upon the currently published HESS results by using more sophisticated tools.