Detection of the Characteristic Pion-Decay Signature in the Molecular Clouds

الأصل · EN

The γ-ray emission from molecular clouds is widely believed to have a hadronic origin, while unequivocal evidence is still lacking. In this work, we analyze the Fermi-LAT Pass 8 publicly available data accumulated from 2008 August 4 to 2017 June 29 and report the significant detection of a characteristic π⁰-decay feature in the γ-ray spectra of the molecular clouds Orion A and Orion B. This detection provides a direct evidence for the hadronic origin of their γ-ray emission.