Title: Measuring Cosmic Rays Using Gamma-Ray Astronomy

Speaker: Professor Yang Ruizhi (University of Science and Technology of China)

Time: 9:30am, October 17, 2025

Location: 3-302, PMO Xianlin Campus

Abstract: Cosmic ray (CR) is one of the most important components in the interstellar medium (ISM), and the origin of CRs remains a mystery.  The diffusion of CRs in turbulent magnetic fields erases the information on the distribution of CR accelerators to a large extent. The energy-dependent diffusion of CRs also significantly modifies the initial (acceleration) spectra of CRs. In this regard, gamma-rays, the secondary products of interactions of CRs with gas and photons in the ISM, provide us more information about the origin of CRs. More specifically, the gamma-ray emissions associated with gas can be used to study the distribution of CRs throughout the Galaxy; the discrete gamma-ray sources can elucidate the locations of individual CR accelerators.  In this talk, I will review the recent advances of gamma-ray astronomy and focus on their implications for CR sciences.