Revealing Large-Scale Structure and Galaxy Evolution at z~2-3 with 3D Tomography of the Intergalactic Medium

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K14755
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 16010:Astronomy-related
• Research Institution: The University of Tokyo
• Principal Investigator: Lee Khee Gan 東京大学, カブリ数物連携宇宙研究機構, 特任講師 (10822091)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: galaxies / cosmic web / cosmology / intergalactic medium / astrophysics

Outline of Final Research Achievements

The large-scale structure of the Universe forms the cosmic web on scales of millions of light-years. While most of the past research on this topic has focused on observations in the nearby Universe, this project has made several achievements in extending this to the more distant Universe, where the light has to travel up to 10 billion light-years to reach us. To do this, we have built novel techniques to create accurate maps of the structure based on observational data from telescopes. Through the data on galaxy positions, we made the first computer simulations that are based directly on the distant observed Universe, allowing us to identify new galaxy protoclusters and predict their fate. Using hydrogen absorption seen in the background galaxy spectra, we made the first 3D maps of the filaments and voids of the cosmic web as traced by the intergalactic gas. These projects allowed us to identify a protocluster that might be the first known site of 'warm-hot intergalactic medium' gas.

Free Research Field

Astrophysics

Academic Significance and Societal Importance of the Research Achievements

宇宙の物質は、宇宙の網と呼ばれるフィラメント状の構造に沿って分布しています。 宇宙網内のガスと銀河の研究をより遠い過去の宇宙にまで推し進めることで、網構造内の重力不安定性の発展や、宇宙の星形成のピーク時からの銀河進化のプロセスを明らかにできます。さらに、 宇宙初期の暖かい銀河間ガスの発見は、原始的な銀河間ガスが、現在の複雑な状態に変化することも明らかにするでしょう。