Multiwavelength Analysis of Galactic Supernova Remnants

TL;DR

This study uses multiwavelength data and radiative modeling to evaluate the hadronic contribution in Galactic supernova remnants, identifying potential PeVatrons and advancing understanding of cosmic ray acceleration mechanisms.

Contribution

It provides a comparative analysis of leptonic and lepto-hadronic models for SNRs, highlighting the importance of hadronic processes and identifying promising PeVatron candidates.

Findings

Lepto-hadronic scenario is favored for most SNRs.

Data around the {} production threshold indicates hadronic contribution.

Some SNRs show hadronic contribution up to a few TeV, suggesting they are PeVatron candidates.

Abstract

The origin of Galactic Cosmic Rays (CRs) and the possibility of Supernova Remnants (SNRs) being potential CR accelerators is still an open debate. The charged CRs can be detected indirectly by the {\gamma}-ray observatories through the {\pi^0} production and consequent decay, leading to the generation of high-energy {\gamma}-rays. The goal of the study is to identify qualitative and quantitative trends in favour of hadronic scenario and search for SNRs which could be potential accelerators up to PeV energies (PeVatrons). We have performed a Multiwavelength (MWL) study using different radiative models to evaluate the hadronic contribution. The spectral energy distributions (SEDs) of selected SNRs are modeled using the Naima [1] package. Two different radiative scenarios are considered, pure leptonic and lepto-hadronic scenarios, and different methods are used to evaluate their importance. This study shows that the lepto-hadronic scenario is favored for most SNRs. Two particular indicators of hadronic contribution come from the data around the {\pi^0} production threshold and the data above a few TeV. The hard rise at the {\pi^0} production threshold cannot be explained by leptonic processes. More data in this region would be valuable for these studies. For some SNRs, an important hadronic contribution is observed up to a few TeV, thus making them promising PeVatron candidates. In this high-energy region where the leptonic processes are expected to be suppressed, more data is required to help distinguish between the leptonic and hadronic origin of {\gamma}-ray emission. In the future, we intend to use the obtained model parameters to simulate data for CTA and assess its capability to identify PeVatrons.