2026-02-27 東京大学
観測されたフッ素の存在量と理論モデルの比較
＜関連情報＞
- https://www.s.u-tokyo.ac.jp/ja/press/11077/
- https://iopscience.iop.org/article/10.3847/2041-8213/ae36a2
z = 6の塵星形成銀河におけるHF(1–0)吸収の上限：初期フッ素濃縮への制約 Upper Limit on HF(1–0) Absorption in a Dusty Star-forming Galaxy at z = 6: Constraints on Early Fluorine Enrichment
Akiyoshi Tsujita, Chiaki Kobayashi, Yuki Yoshimura, Kotaro Kohno, Ken-ichi Tadaki, Fumiya Maeda, Hideki Umehata, Shuo Huang, Bunyo Hatsukade, Fumi Egusa,…
The Astrophysical Journal Letters Published: 2026 February 27
DOI:10.3847/2041-8213/ae36a2
Abstract
Wolf–Rayet (WR) stars have recently attracted attention as possible drivers of early chemical enrichment, including the production of fluorine, whose nucleosynthetic origin remains debated. To test the contribution of massive stars to fluorine production in the early Universe, we conducted Atacama Large Millimeter/ submillimeter Array Band 5 spectroscopy of the HF(1–0) absorption line toward a dusty star-forming galaxy at z = 6.024. This galaxy has a known gas-phase metallicity and is too young for low-mass asymptotic giant branch stars to have contributed significantly, providing a clean environment to isolate massive-star yields. We do not detect significant HF absorption (∼2σ) and derive a conservative 5σ upper limit of NHF/NH2 ＜2.2×10-9 . This limit is about an order of magnitude below typical local measurements, indicating inefficient fluorine enrichment ∼0.9 Gyr after the Big Bang. Comparison with chemical evolution models shows that our constraint is consistent with scenarios without WR yields at this epoch. Expanding the sample of HF absorption measurements in highredshift galaxies with well-characterized metallicities will be crucial for tracing the onset of WR enrichment and fluorine production across cosmic time.
