| Project/Area Number |
17H06599
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Single-year Grants |
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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 |
Koehlinger Fabian 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (70800556)
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| Project Period (FY) |
2017-08-25 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
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| Keywords | intrinsic alignments / consistency / cosmic shear / HSC / Cosmology(experiment) / Gravitation / Cosmology (experiment) |
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| Outline of Final Research Achievements |
When light rays of galaxies travel through the large-scale structure of the Universe to an observer, their paths are deflected by all intervening mass according to Einstein’s General Relativity theory. Measurements of these tiny deflections from millions of galaxy images taken in large surveys of the night sky are used to derive cosmological parameters.Measuring these tiny image distortions is a challenging task and further complicated by particular galaxy alignments along the line-of-sight which can dilute or strengthen the true cosmological signal. If these extra contributions are left unaccounted for, the derived cosmological parameters from this probe will be biased.Eventually, the derived cosmological parameters also need to be compared to results from other independent probes.Addressing both issues, i.e. measuring intrinsic galaxy alignments and presenting a novel and statistically robust way of comparing results within and across probes are the key achievements of this project.
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| Academic Significance and Societal Importance of the Research Achievements |
様々な銀河サーベイが行われている今、各サーベイが行った宇宙論解析結果を厳密に比較する統計手法の確立の重要性は計り知れない。宇宙論解析は、たとえそれが同じような手法であってもデータの性質や手法の細かな手順が異なるため単純に結果のみを比較することはできない。またそれ以前にデータの性質と解析手法の妥当性を評価する必要がある。そのためこの研究ではデータと解析手法の一貫性を評価する統計手法を確立した。これは宇宙論解析だけでなくその他の分野にも適用可能な汎用性の高い手法である。また、他に重力レンズ効果シグナルにおける銀河の形状と潮汐力場の相関の系統誤差としての寄与を間接的に測定することにも成功した。
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