Probing the hadronic nature of the gamma-ray emission associated with Westerlund 2

ABSTRACT Star-forming regions have been proposed as potential Galactic cosmic ray accelerators for decades. Cosmic acceleration can be probed through observations of gamma-rays produced in inelastic proton–proton collisions at GeV and TeV energies. In this paper, we analyse more than 11 yr Fermi–LAT data from the direction Westerlund 2, one most massive best-studied star-forming our Galaxy. particular, investigate characteristics bright pulsar PSR J1023–5746 that dominates gamma-ray emission below a few position 2 underlying extended source FGES J1023.3–5747. The analysis results clear identification J1023.3–5747 counterpart HESS J1023-575, its morphological spectral properties. This provides new clues about origin J1023-575 emission, favouring hadronic powered by rather leptonic related to either wind nebula associated with or cluster itself. result indirectly supports hypothesis contribute sea observed