Theory Seminar

KEK 素粒子原子核研究所・理論セミナー



The possible origins of heavy nuclei ultra-high energy cosmic rays


(in English)


Dr. Shunsaku Horiuchi

(Ohio State University)


August 30 (Tue.) 11:00-12:00


Kenkyu Honkan 1F, Meeting Room 1  



 A century after their discovery, the astrophysical origins of cosmic rays remain intensely studied. In particular, cosmic rays of the highest energies cannot feasibly be confined in our Galaxy, and is thought to originate from extra-galactic sources. While many source candidates have been proposed, disentangling them is generally complicated by the fact that charged cosmic rays bend in the magnetic universe. However, new observational results on the composition may provide new insights. It has recently been reported that the composition of cosmic rays at the highest energies become increasingly heavy (Fe-like). I will review the composition claims and discuss implications for source candidates. In particular, I will discuss the potential that explosive nucleosynthesis in gamma-ray burst jets can provide a uniquely heavy-nuclei-dominated cosmic ray source.