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赤道偏移 z = 8.6 の銀河のスペクトロスコープによる確認
M D Lehnert1, N P H Nesvadba, J-G Cuby
1GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, 5 Place Jules Janssen, 92190 Meudon, France. matthew.lehnert@obspm.fr
Nature
|October 22, 2010
まとめ
天文学者は,ビッグバンから6億年未満の銀河からライマン・アルファ (Lyα) 光子を検出しました. この銀河は赤道偏移 z = 8.5549 で,初期の宇宙に関する重要な洞察を提供します.
科学分野:
- 宇宙学と銀河外天文学
- 初期の宇宙に関する研究.
- 銀河の進化と再イオン化について
背景:
- 初期の銀河の最初の星は,銀河間介質をイオン化し,宇宙に大きな影響を与えた.
- 複合的なプロセスである再イオン化は,ビッグバンから約10億年後に完成した (赤色移転 z ≈ 6).
- 遠い銀河からのイオン化フォトンの検出は,再イオン化の原因となる源を制限する.
研究 の 目的:
- 初期の宇宙の銀河からライマン・アルファ (Lyα) 光子を検出する.
- 再イオン化の源のタイミング,場所,性質に制約を課す.
- 研究の時点で知られている最も遠い銀河を特定するために.
主な方法:
- 銀河からのライマン・アルファ (Lyα) 放射線の観測と検出.
- 赤差と距離を決定するスペクトル解析.
- 以前に知られている最も遠い物体との比較.
主要な成果:
- 銀河UDFy-38135539からのLyα光子の検出 z = 8.5549 ± 0.0002.39の赤偏移で
- この銀河は,ビッグバンから6億年以内に観測された,報告の時点で知られている最も遠い物体です.
- 検出された単一の源は,Lyαの脱出に必要な体積をイオン化するのに不十分であり,近くの弱体銀河からの貢献を暗示しています.
結論:
- 検出された銀河は,初期の銀河形成の証拠と,宇宙再イオン化におけるその役割を提供する.
- 再イオニゼーションには,多くの,おそらくより薄暗い銀河の集合的貢献が含まれる可能性が高い.
- 再イオン化過程と弱々しい銀河群の貢献を完全に理解するために,さらなる観測が必要である.
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