Precise measurements of density fluctuations using wide-field imaging surveys

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K03693
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 16010:Astronomy-related
• Research Institution: Chiba University (2021-2022); The University of Tokyo (2018-2020)
• Principal Investigator: Oguri Masamune 千葉大学, 先進科学センター, 教授 (60598572)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 宇宙論 / 重力レンズ

Outline of Final Research Achievements

Analysis of wide-sky imaging surveys, in particular the Hyper Suprime-Cam (HSC) survey data from the Subaru Telescope, and related theoretical studies have yielded significant progress in measuring total density fluctuations of the Universe. Compared to the total amount of density fluctuations expected from the extrapolation of the cosmic background radiation, the density fluctuations obtained from the gravitational lensing analysis of the third-year data of the HSC survey are about 2 sigma less, which is interesting and suggests a failure of standard cosmology. A systematic analysis of the gravitational lensing of galaxy clusters has revealed that the mass distribution of galaxy clusters is simpler than expected, opening the way to cosmology using clusters of galaxies.

Free Research Field

宇宙物理学

Academic Significance and Societal Importance of the Research Achievements

宇宙全体の進化についての重量な研究成果が得られた。標準的な宇宙論の綻びの兆候を捉えたものであり、宇宙論の最大の謎であるダークマター、ダークエネルギーの正体に迫る重要な研究成果が得られた。これらの成果の多くは日本の国立天文台が運用するすばる望遠鏡を用いた成果であり、国際社会における日本のプレゼンス向上にも貢献できた。