To build and test a phenomenological model of ultra-high energy cosmic rays

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K17685
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: The University of Tokyo
• Principal Investigator: Kido Eiji 東京大学, 宇宙線研究所, 特任助教 (00633778)
• Research Collaborator: Kalashev O. ; Thomson G. ; Tinyakov P. ; NAGATAKI Shigehiro
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: UHECR

Outline of Final Research Achievements

We fit the energy spectra observed by the Telescope Array (TA) and Telescope Array Low Energy extension (TALE) experiment using phenomenological extragalactic cosmic ray proton source model assuming some models of galactic cosmic rays. The fit range is from about 30 PeV to 10 EeV including the energy region known as “second knee” and “ankle”. We assume the following conditions of the sources. The energy spectrum of cosmic ray protons is power law and the power index is -α at the source. The cosmic ray source density per comoving unit volume is the power law of (1 + z) and the power index is m until z = Zc and constant for the sources at z > Zc. α=2.38+0.04-0.04，m=3.6+0.2-0.3 is obtained by the fitting. The constraint of Zc is obtained assuming some models of cosmological magnetic fields.

Free Research Field

宇宙線物理学