Exploring energy spectrum anisotropies in ultra-high energy cosmic rays with the Telescope Array

• Project/Area Number: 18H03705
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 15:Particle-, nuclear-, astro-physics, and related fields
• Research Institution: Osaka Metropolitan University (2022); Osaka City University (2018-2021)
• Principal Investigator: 常定 芳基 大阪公立大学, 大学院理学研究科, 教授 (50401526)
• Co-Investigator(Kenkyū-buntansha): 竹田 成宏 東京大学, 宇宙線研究所, 助教 (40360581) ; 有働 慈治 神奈川大学, 工学部, 准教授 (50506714) ; 冨田 孝幸 信州大学, 学術研究院工学系, 助教 (70632975) ; 多米田 裕一郎 大阪電気通信大学, 工学部, 准教授 (90467019)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥43,810,000 (Direct Cost: ¥33,700,000、Indirect Cost: ¥10,110,000); Fiscal Year 2022: ¥7,670,000 (Direct Cost: ¥5,900,000、Indirect Cost: ¥1,770,000); Fiscal Year 2021: ¥7,670,000 (Direct Cost: ¥5,900,000、Indirect Cost: ¥1,770,000); Fiscal Year 2020: ¥7,670,000 (Direct Cost: ¥5,900,000、Indirect Cost: ¥1,770,000); Fiscal Year 2019: ¥10,530,000 (Direct Cost: ¥8,100,000、Indirect Cost: ¥2,430,000); Fiscal Year 2018: ¥10,270,000 (Direct Cost: ¥7,900,000、Indirect Cost: ¥2,370,000)
• Keywords: 超高エネルギー宇宙線 / 宇宙線 / エネルギースペクトル

Outline of Annual Research Achievements

本研究は10の18乗電子ボルト (eV) を超える放射線である超高エネルギー宇宙線の起源天体に迫るとともに、この宇宙における最も激烈な天体現象の物理を解明することを目的としている。米国ユタ州に建設した検出器「テレスコープアレイ(TA)」を長期間運用し、２種類の検出器、「地表検出器」と「大気蛍光望遠鏡」によるハイブリッド観測によりエネルギースペクトルの異方性を決定することが主眼である。本研究では特にテレスコープアレイの拡張実験である"TAx4" を安定的に運用することが重要であった。2020年度はコロナ禍のために現地での検出器メンテナンスや対面実施での解析ミーティングなどを行うことができなかったが、遠隔操作による検出器運用によって可能な限りのデータ取得を行い、データ解析につなげた。2022年度以降は遠隔運用が軌道に乗り、渡航の機会は減らしつつ検出器稼働状況はコロナ以前の水準にまで回復した。そして得られた宇宙線のエネルギー分布、および到来方向を調べ、TAの視野において北方向から到来する宇宙線と、南方向から到来する宇宙線の到来頻度を調べ、エネルギースペクトルの形状が異なる可能性が示唆された。さらに既に報告されている宇宙線過剰領域 "Hot Spot"、および銀河団 PPSC の方向のエネルギースペクトルが他の領域とは異なる兆候を見出している。また2021年5月には観測史上２番目の高エネルギーであり「アマテラス粒子」として知られることになるイベントを観測した。またエネルギースペクトルの形状には複数の折れ曲がり構造として既知の "ankle"、 "cutoff" に加え、10の19.5乗eV付近に第３の折れ曲がり（足の甲に当たる "instep" という呼称が提案されている）が見つかった。これは南半球で観測結果とも一致する結果であった。

Research Progress Status

令和4年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和4年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] ユタ大学(米国)
• [Int'l Joint Research] Hanyang University/Sungkyunkwan University(韓国)
• [Int'l Joint Research] INR of the Russian Academy of Sciences(ロシア連邦)
• [Int'l Joint Research] ブリュッセル自由大学(ベルギー)
• [Int'l Joint Research] University of Utah(米国)
• [Int'l Joint Research] Institute of Nuclear Research/Moscow State University(ロシア連邦)
• [Int'l Joint Research] Sungyunkhan University/Hanyang University(韓国)
• [Int'l Joint Research] Universite Libre de Bruxelles(ベルギー)
• [Journal Article] An extremely energetic cosmic ray observed by a surface detector array (2023)
  • Author(s): Telescope Array Collaboration
  • Journal Title: Science Volume: 382 Issue: 6673 Pages: 903-907
  • DOI: 10.1126/science.abo5095
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Ultra high energy cosmic rays The intersection of the Cosmic and Energy Frontiers (2023)
  • Author(s): Coleman A., et al.
  • Journal Title: Astroparticle Physics Volume: 149 Pages: 102819-102819
  • DOI: 10.1016/j.astropartphys.2023.102819
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Search for Spatial Correlations of Neutrinos with Ultra-high-energy Cosmic Rays (2022)
  • Author(s): Albert A. et al.
  • Journal Title: The Astrophysical Journal Volume: 934 Issue: 2 Pages: 164-164
  • DOI: 10.3847/1538-4357/ac6def
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Deep learning method for identifying mass composition of ultra-high-energy cosmic rays (2022)
  • Author(s): Kalashev O.、Kharuk I.、Kuznetsov M.、Rubtsov G.、Sako T.、Tsunesada Y.、Zhezher Ya.
  • Journal Title: Journal of Instrumentation Volume: 17 Issue: 05 Pages: P05008-P05008
  • DOI: 10.1088/1748-0221/17/05/p05008
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Observation of variations in cosmic ray single count rates during thunderstorms and implications for large-scale electric field changes (2022)
  • Author(s): Abbasi R.U. et al.
  • Journal Title: Physical Review D Volume: 105 Issue: 6 Pages: 062002-062002
  • DOI: 10.1103/physrevd.105.062002
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Surface detectors of the TAx4 experiment (2021)
  • Author(s): R.U.Abbasi et al. (Telescope Array Collaboration)
  • Journal Title: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Volume: 1019 Pages: 165726-165726
  • DOI: 10.1016/j.nima.2021.165726
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] The Cosmic-Ray Composition between 2 PeV and 2 EeV Observed with the TALE Detector in Monocular Mode (2021)
  • Author(s): Abbasi R. U. et al. (Telescope Array collaboration)
  • Journal Title: The Astrophysical Journal Volume: 909 Issue: 2 Pages: 178-178
  • DOI: 10.3847/1538-4357/abdd30
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Measurement of the proton-air cross section with Telescope Array’s Black Rock Mesa and Long Ridge fluorescence detectors, and surface array in hybrid mode (2020)
  • Author(s): Abbasi R.U. et al. (Telescope Array collboration)
  • Journal Title: Physical Review D Volume: 102 Issue: 6 Pages: 1-13
  • DOI: 10.1103/physrevd.102.062004
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Evidence for a Supergalactic Structure of Magnetic Deflection Multiplets of Ultra-high-energy Cosmic Rays (2020)
  • Author(s): Abbasi R. U. et al. (Telescope Array collboration)
  • Journal Title: The Astrophysical Journal Volume: 899 Issue: 1 Pages: 86-86
  • DOI: 10.3847/1538-4357/aba26c
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Observations of the Origin of Downward Terrestrial Gamma‐Ray Flashes (2020)
  • Author(s): Belz J. W. et al. (Telescope Array collboration)
  • Journal Title: Journal of Geophysical Research: Atmospheres Volume: 125 Issue: 23 Pages: 1-26
  • DOI: 10.1029/2019jd031940
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Search for Large-scale Anisotropy on Arrival Directions of Ultra-high-energy Cosmic Rays Observed with the Telescope Array Experiment (2020)
  • Author(s): Abbasi R. U. et al. (Telescope Array collboration)
  • Journal Title: The Astrophysical Journal Volume: 898 Issue: 2 Pages: L28-L28
  • DOI: 10.3847/2041-8213/aba0bc
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Search for Ultra-High-Energy Neutrinos with the Telescope Array Surface Detector (2020)
  • Author(s): R.U. Abbasi et al.
  • Journal Title: Journal of Experimental And Theoretical Physics Volume: -
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Search for point sources of ultra-high-energy photons with the Telescope Array surface detector (2020)
  • Author(s): R.U. Abbasi et al.
  • Journal Title: Monthly Notices of Royal Astronomical Society Volume: 492 Pages: 3984-3993
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Constraints on the diffuse photon flux with energies above 1018?eV using the surface detector of the Telescope Array experiment (2019)
  • Author(s): R.U. Abbasi et. al.
  • Journal Title: Astroparticle Physics Volume: 110 Pages: 8-14
  • DOI: 10.1016/j.astropartphys.2019.03.003
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Telescope Arrayによる最高エネルギー宇宙線観測 -兆候の発見から精密観測へ- (2019)
  • Author(s): 荻尾彰一、常定芳基、佐川宏行
  • Journal Title: Radioisotopes Volume: 68 Pages: 843-856
  • NAID: 130007761351
  • Peer Reviewed
• [Journal Article] Study of muons from ultrahigh energy cosmic ray air showers measured with the Telescope Array experiment (2018)
  • Author(s): R. U. Abbasi et al.
  • Journal Title: Physical Review D Volume: 98 Issue: 2 Pages: 022002-022002
  • DOI: 10.1103/physrevd.98.022002
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Depth of Ultra High Energy Cosmic Ray Induced Air Shower Maxima Measured by the Telescope Array Black Rock and Long Ridge FADC Fluorescence Detectors and Surface Array in Hybrid Mode (2018)
  • Author(s): R.U. Abbasi et. al.
  • Journal Title: Astrophysical Journal Volume: 858 Pages: 76-76
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Testing a Reported Correlation between Arrival Directions of Ultra-high-energy Cosmic Rays and a Flux Pattern from nearby Starburst Galaxies using Telescope Array Data (2018)
  • Author(s): R.U. Abbasi et. al.
  • Journal Title: Astrophysical Journal Letters Volume: 867
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Evidence of Intermediate-scale Energy Spectrum Anisotropy of Cosmic Rays E >= 10(19.2)eV with the Telescope Array Surface Detector (2018)
  • Author(s): R.U. Abbasi et. al.
  • Journal Title: Astrophysical Journal Volume: 862 Pages: 91-91
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Gamma Ray Showers Observed at Ground Level in Coincidence With Downward Lightning Leaders (2018)
  • Author(s): R.U. Abbasi et. al.
  • Journal Title: Journal of Geophysical Research: Atmospheres Volume: 123 Issue: 13 Pages: 6864-6879
  • DOI: 10.1029/2017jd027931
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] The Cosmic Ray Energy Spectrum between 2PeV and 2EeV Observed with the TALE Detector in Monocular Mode (2018)
  • Author(s): R.U. Abbasi et. al.
  • Journal Title: Astrophysical Journal Volume: 865 Pages: 1-1
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Measurement of UHECR energy spectrum with the Pierre Auger Observatory and the Telescope Array (2023)
  • Author(s): Yoshiki Tsunesada
  • Organizer: ICRC2023 Nagoya
  • Int'l Joint Research
• [Presentation] Recent results from the Telescope Array (2022)
  • Author(s): Yoshiki Tsunesada
  • Organizer: THE GOLDEN UNIVERSE: Nuclear Astrophysics and Cosmic Rays in the Multimessenger Era ICISE Quy Nhon Vietnam
  • Int'l Joint Research / Invited
• [Presentation] The energy spectrum of ultra-high energy cosmic rays measured at the Pierre Auger Observatory and at the Telescope Array (2019)
  • Author(s): O.Deligny, D.Ikeda, E.Kido, S.Ogio, S.Nagataki, H.Sagawa, T.Nonaka, M.Takeda, Y.Tsunesada, S.Udo et al. (Telescope Array Collaboration)
  • Organizer: International Cosmic Ray Conference (ICRC2019)
  • Int'l Joint Research
• [Presentation] SUPERGALACTIC STRUCTURE OF ENERGY-ANGLE CORRELATIONS (2019)
  • Author(s): J.P.Lundquist, D.Ikeda, E.Kido, S.Ogio, S.Nagataki, H.Sagawa, T.Nonaka, M.Takeda, Y.Tsunesada, S.Udo et al. (Telescope Array Collaboration)
  • Organizer: International Cosmic Ray Conference (ICRC2019)
  • Int'l Joint Research
• [Presentation] TA実験327：地表粒子検出器アレイによるTAホットスポットの最新結果 (2019)
  • Author(s): 川田和正、池田大輔、有働慈治、荻尾彰一、木戸英治、佐川宏行、竹田成宏、常定芳基、長瀧重博、野中敏幸、他Telescope Array Collaboration
  • Organizer: 日本物理学会 2019年秋季大会
• [Presentation] TA実験329：TAx4実験全体報告5 (2019)
  • Author(s): 木戸英治、池田大輔、有働慈治、荻尾彰一、佐川宏行、竹田成宏、常定芳基、野中敏幸、他Telescope Array Collaboration
  • Organizer: 日本物理学会 2019年秋季大会
• [Presentation] Recent results and status of the Telescope Array Experiment (2019)
  • Author(s): E.Kido, D.Ikeda, S.Ogio, S.Nagataki, H.Sagawa, T.Nonaka, M.Takeda, Y.Tsunesada, S.Udo et al. (Telescope Array Collaboration)
  • Organizer: The 2019 TeV Particle Astrophysics conference（TeVPA 2019）（国際学会）
  • Int'l Joint Research / Invited
• [Presentation] TA実験336：10^{18.5}eV以上のEAS粒子ディスク時空間構造とEAS発達(5) (2019)
  • Author(s): 仲田海人、常定芳基、野中敏幸、佐川宏行、他Telescope Array Collaboration
  • Organizer: "日本物理学会 第75回年次大会"
• [Presentation] Latest results form TA (2018)
  • Author(s): Yoshiki Tsunesada
  • Organizer: "AMS Days at La Palma", La Palma, Spain
  • Int'l Joint Research / Invited
• [Presentation] Telescope Array Experiment (2018)
  • Author(s): Shoichi Ogio
  • Organizer: ISVHECRI2018, Nagoya, Japan
  • Int'l Joint Research / Invited
• [Presentation] Recent results from the Telescope Array (2018)
  • Author(s): Yoshiki Tsunesada
  • Organizer: "QCD at Cosmic Energies VII", Riga, Latvia
  • Int'l Joint Research / Invited
• [Presentation] Results from the Telescope Array Experiment (2018)
  • Author(s): Charles Jui
  • Organizer: CRIS2018, Scitilia, Italy
  • Int'l Joint Research / Invited
• [Presentation] TA/Lightning (2018)
  • Author(s): John Belz
  • Organizer: ICAE, Nara, Japan
  • Int'l Joint Research / Invited
• [Presentation] Highlights from the Telescope Array Experiment (2018)
  • Author(s): Il Park
  • Organizer: The 39th ICHEP, Seoul, Korea
  • Int'l Joint Research / Invited
• [Presentation] Observation of EHE Cosmic Rays with the Telescope Array Experiment (2018)
  • Author(s): Masahiro Takeda
  • Organizer: ICNFP2018, Crete, Greece
  • Int'l Joint Research / Invited
• [Presentation] Summary of Results from the Telescope Array Experiment (2018)
  • Author(s): Maxim Prishkov
  • Organizer: The 26th E+CRS/35th RCRC
  • Int'l Joint Research / Invited
• [Presentation] Latest results and current status of theTelescope Array Experiment (2018)
  • Author(s): Shoichi Ogio
  • Organizer: VHEPU 2018, Quy Nhon, Vietnam
  • Int'l Joint Research / Invited
• [Presentation] Telescope Array Experiment (2018)
  • Author(s): Dmitri Ivanov
  • Organizer: TeVPA 2018, Berlin, Germany
  • Int'l Joint Research / Invited
• [Presentation] Recent results of the Telescope Array Experiment on ultra-high energy cosmic rays and TA extension (2018)
  • Author(s): Hiroyuki Sagawa
  • Organizer: PACIFIC2018, Moorea, French Polynesia
  • Int'l Joint Research / Invited
• [Presentation] Observation of Ultra-High-Energy Cosmic Rays with the Telescope Array Experiment (2018)
  • Author(s): Kazumasa Kawata
  • Organizer: IWARA2018, Peru
  • Int'l Joint Research / Invited
• [Presentation] Status and results of the Telescope Array Observatory (2018)
  • Author(s): Grigory Rubtsov
  • Organizer: WASDHA2018, Moscow, Russia
  • Int'l Joint Research / Invited
• [Presentation] TA/Lightning (2018)
  • Author(s): Rasha Abbasi
  • Organizer: AtmoHEAD2018, Capri, Italy
  • Int'l Joint Research / Invited
• [Presentation] TA Spectrum (2018)
  • Author(s): Dmtri Ivanov
  • Organizer: UHECR2018, Paris, France
  • Int'l Joint Research / Invited
• [Presentation] The Telescope Array experiment (2018)
  • Author(s): Armando di Matteo
  • Organizer: eXtreme2019
  • Int'l Joint Research / Invited
• [Presentation] Recent results from the Telescope Array experiment (2018)
  • Author(s): Masahiro Takeda
  • Organizer: The 10th VHEPA Workshop, ICRR, Japan
  • Int'l Joint Research / Invited
• [Presentation] Report on the discrepancy of muon densities between data and MC from cosmic ray air shower experiments (2018)
  • Author(s): Ryuji Takeishi
  • Organizer: Workshop for Atmospheric Neutrino Production in the MeV to PeV range, Nagoya, Japan
  • Int'l Joint Research / Invited
• [Book] 宇宙の観測III 第2版 (シリーズ現代の天文学) (2019)
  • Author(s): 井上、小山、高橋、水本、常定ほか
  • Total Pages: 324
  • Publisher: 日本評論社
  • ISBN: 4535607672