报告题目: Pinning down the origin of Galactic cosmic rays by using gamma-ray observations

　　报告人：杨睿智（德国马普核物理研究所博士后）

　　摘要: The origin of Cosmic rays (CRs) still remains as a mystery. The diffusion of CRs in turbulent magnetic fields erases the information on the distribution of CR accelerators. The energy dependent diffusion of CRs also significantly modifies the initial (acceleration) spectra of CRs. As a result, gamma-rays, the secondaries from CR interaction with ambient gas, tell us more information about the origin of CRs. This can be done in two ways:

　　1. the gamma-ray emissions, especially those associated with ambient gas, can be used to study the distribution of CR throughout the Galaxy. In this regard I will discuss the latest results of CR radial distribution by analysing the Fermi LAT as well as CO/HI/Infrared data.

　　2. the discrete gamma-ray sources can elucidate the locations of individual CR accelerators. Here I will report the recent detection of extended young star cluster NGC 3603 and Westerlund 2.

　　时间：4月18日（周二）上午10点

　　地点：天文楼502会议室

欢迎各位老师、同学参加！

　                                     　南京大学天文与空间科学学院