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2014 Fiscal Year Final Research Report

Study of Cosmic-Ray Anisotropy in the Ultra-High-Energy Ankle Region

Research Project

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Project/Area Number 25800128
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeMulti-year Fund
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionThe University of Tokyo

Principal Investigator

KAWATA Kazumasa  東京大学, 宇宙線研究所, 特任助教 (10401291)

Project Period (FY) 2013-04-01 – 2015-03-31
Keywords宇宙線 / 極高エネルギー宇宙線 / 宇宙線異方性
Outline of Final Research Achievements

The highest-energy cosmic rays (100EeV =100 exa-electron volt) observed at the earth have energy of 10 million times larger than that of protons produced in any terrestrial particle accelerators. The origin of the highest-energy cosmic rays is one of mystery in the modern physics. In this research, we searched for cosmic-ray excess / deficit (cosmic-ray anisotropy) using the data above 1 EeV collected by the Telescope Array experiment. As a result, we found no significant cosmic ray anisotropy around 1 EeV. However, this observation achieved the best sensitivity in the northern sky survey. In the energy region above 57 EeV, we found an indication of the cosmic-ray excess, which is called "hotspot", in the vicinity of the Ursa Major galaxy cluster.

Free Research Field

宇宙線物理学

URL: 

Published: 2016-06-03  

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