2014 Fiscal Year Final Research Report
Study of Cosmic-Ray Anisotropy in the Ultra-High-Energy Ankle Region
| Project/Area Number |
25800128
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Project Period (FY) |
2013-04-01 – 2015-03-31
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| Keywords | 宇宙線 / 極高エネルギー宇宙線 / 宇宙線異方性 |
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| 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.
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| Free Research Field |
宇宙線物理学
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