Title: Search for Ultrahigh-Energy Cosmic Ray Sources 

Speaker: Dr. Eiji Kido (Institute of Cosmic Ray Research, University of Tokyo) 

Abstract: The sources of ultrahigh-energy cosmic rays (UHECRs) remain unknown. Observing UHECRs at higher energies is key to identifying their origins, as higher-energy cosmic rays experience smaller magnetic deflections and have shorter propagation distances. However, such observations require a large detection area due to the extreme rarity of UHECRs at these energies. My research has primarily focused on developing the surface detector array of the Telescope Array (TA) Experiment and its high-energy extension, TAx4. The Pierre Auger Observatory and the TAx4 Experiment have achieved large detection areas of approximately 3,000 km² in the Southern Hemisphere and 1,700 km² in the Northern Hemisphere, respectively. Both experiments have conducted stable UHECR observations over many years. Recently, the Auger-TA Anisotropy Working Group reported a 4.6σ correlation between the arrival directions of UHECRs and nearby gamma-ray-emitting starburst galaxies. This anisotropy is narrowing down the possible UHECR source candidates. Identifying the origin of cosmic rays remains an urgent issue. In this seminar, I will first provide an overview of UHECR observations, followed by a discussion of our recent analysis aimed at identifying UHECR sources using observational data.

Date: 14:00, Feb. 19 (Wednesday)  

Place: 3-402

欢迎大家参加！