宇宙時間 の 最初 の 10 億 年 に 見 られ た 炭酸 塵 の 粒
Joris Witstok1,2, Irene Shivaei3, Renske Smit4
1Kavli Institute for Cosmology, University of Cambridge, Cambridge, UK. jnw30@cam.ac.uk.
Nature
|July 19, 2023
まとめ
初期の銀河は 大量の塵を急速に形成した. 観測により,赤道移転7までの銀河の2,175 Åの塵の特徴が明らかになり,初期の宇宙における急速な塵の生成過程を示唆している.
科学分野:
- 宇宙塵の形成
- 初期の宇宙 銀河の進化
- 遠くの銀河のスペクトル解析
背景:
- 大きな塵の貯蔵庫 (10^8 Mまで) は,赤道偏移 z8 (宇宙年齢 ~ 600 Myr) の銀河で観測されています.
- 現存する塵の形成理論は このような短い宇宙の時間スケールでの 急速な塵の生成を説明するのに苦労しています
- 以前の研究では,総粉塵量に依拠しており,粉塵の発生場所の特定に曖昧さをもたらしました.
研究 の 目的:
- 初期の銀河における2,175 Åの塵衰弱特性の存在と影響を調査する.
- 塵の形成の時間スケールを制限し,初期の宇宙における潜在的な生産メカニズムを特定する.
- 赤外線スペクトロスコーピーを利用して 高赤偏移の銀河の塵の性質を調査する.
主な方法:
- 赤偏差 z7で観測された近赤外線スペクトル.
- 2,175 Åの塵衰弱特性の存在について分析したスペクトルデータ.
- ミルクウェイと赤道偏移の低い銀河の既知の塵の特徴と比較した.
主要な成果:
- 銀河の2175 Åの塵の特徴を z7 (宇宙時間の最初の10億年以内に) まで検出した.
- この特徴の存在は,急速な時間スケールの中で炭酸粒子の形成を意味します.
- この発見は既存のモデルに異議を唱え 特定の急速な塵の発生場所を示唆している.
結論:
- 炭素の粒子の急速な形成は 初期の宇宙で確認されています
- この急速な塵生成の潜在的な場所には,ウルフ・レイエの星や超新星噴出物があります.
- この研究は,初期の宇宙における塵の形成と銀河の進化のモデルに新しい観測的制約を提供します.
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