Observational study of star-formation and chemical enrichment in the youngest galaxies

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K22373
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0204:Astronomy, earth and planetary science, and related fields
• Research Institution: National Astronomical Observatory of Japan
• Principal Investigator: Nakajima Kimihiko 国立天文台, 科学研究部, 特任助教 (80875534)
• Project Period (FY): 2020-09-11 – 2024-03-31
• Keywords: 銀河進化 / 化学進化 / 初代銀河 / 星形成

Outline of Final Research Achievements

Through this program, I conducted preparatory research in anticipation of direct observational studies of the early universe using the next-generation James Webb Space Telescope (JWST), which began scientific operations in 2022. I initiated a large-scale survey targeting nearby galaxies with extremely low metallicity and recently formed stars as analogs for early universe objects. This research aimed to elucidate their characteristics and develop observational approaches applicable to distant cosmic objects.
Utilizing the properties and observational techniques refined through this local galaxy project, I advanced direct observational studies of early universe objects with the early release data from JWST. Notably, I successfully conducted high-impact research by observationally constraining the abundance ratios of oxygen, nitrogen, and carbon with respect to hydrogen, addressing fundamental questions about the universe's chemical enrichment history and the evolution of cosmic objects.

Free Research Field

銀河天文学

Academic Significance and Societal Importance of the Research Achievements

本研究は、宇宙の初期段階における銀河の形成と元素合成の進化に関する理解を深める上で重要な貢献を果たした。酸素や窒素の存在比の高精度測定により、初代銀河の特性や元素合成のプロセスに関する新たな知見が得られたことは、宇宙論や天文学の基礎研究において重要な進展である。また、これらの成果は、JWSTや次世代観測装置を活用した未来の天文学研究における指針となる。さらに、研究成果が一般社会にも広く認知されたことにより、宇宙科学への関心を高め、科学教育や啓蒙活動の一助となる社会的意義も大きい。