Search for dark matter and observation of cosmic gamma-rays by CALET
| Project/Area Number |
16K05382
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Ritsumeikan University |
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Principal Investigator |
Mori Masaki 立命館大学, 理工学部, 教授 (80210136)
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| Project Period (FY) |
2016-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Keywords | 天体ガンマ線 / 暗黒物質 / 粒子加速 |
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| Outline of Final Research Achievements |
We analyzed 5-year data acquired with the CALET detector on board the International Space Station and obtained gamma-ray candidates above 10 GeV. We searched for monochromatic (line) gamma-ray signals in the data expected to originate from pair annihilation or decay of dark matter particles.
Assuming four regions of interest in the Galactic center region corresponding to four Galactic halo density profile models, we obtained energy spectra of gamma-ray candidates excluding point source regions. These spectra are consistent with a power-law form with single index. Thus we derived upper limits on fluxes of line gamma-ray signals from the observed spectra. Compared with the expected flux of signal assuming that the Galactic halo consists of dark matter, we calculated limits on the annihilation cross section times the relative velocity for the pair annihilation case and on the lifetime for the decay case. These results will be reported in international conferences and in academic journals.
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| Academic Significance and Societal Importance of the Research Achievements |
ビッグバンで始まった宇宙で、銀河が形成される際の主役は未知の暗黒物質であるとされ、宇宙の質量の大部分を占めると考えられているが、その正体はわかっていない。暗黒物質が未知の重い素粒子であった場合、対消滅や崩壊を起こして、特徴的な単色のガンマ線（ラインガンマ線）を放出することが予想されている。国際宇宙ステーションに設置された宇宙線検出器CALETの約5年分の観測データを用いて、ラインガンマ線の信号を探索したが、そのような徴候は観測されず、暗黒物質の性質についての制限を与える結果を得た。これは、暗黒物質の正体を解明する上での手掛かりを与える重要な結果といえる。
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Report
(6 results)
Research Products
(50 results)
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[Journal Article] CALET Upper Limits on X-Ray and Gamma-Ray Counterparts of GW1512262016
Author(s)
O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, T. Sakamoto, H. Tomida, et al.
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Journal Title
The Astrophysical Journal
Volume: 829
Issue: 1
Pages: 20-24
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
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