静止している巨大な銀河の赤道偏移は 3.717
Karl Glazebrook1, Corentin Schreiber2, Ivo Labbé2
1Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122, Australia.
Nature
|April 7, 2017
まとめ
恒星形成が止まった巨大な銀河は 初期の宇宙で発見されました 赤道3.717の銀河のスペクトル観測は 現在の銀河形成モデルに 異議を唱えます
科学分野:
- 宇宙学 と 銀河 外 の 天文学
- 銀河の形成 と 進化
背景:
- 宇宙初期の大規模な静止銀河は,軽微な紫外線放射のため,観測的に検出が困難である.
- 以前の深層赤外線観測では,このような銀河が赤道偏移 z≈2 で特定され,モデルではその急速な形成が z≈3−4 で説明されている.
- より深い調査は,さらに高い赤偏移で静止している巨大な銀河の集団を示唆したが,これらは理論的なモデルによって予測されなかった.
研究 の 目的:
- 非常に高い赤偏移 (z > 3) で,巨大な静止銀河の存在をスペクトル検査で確認する.
- これらの初期の巨大な銀河の形成の時間スケールとプロセスを調査する.
- 初期の銀河の組成に関する現在の理論モデルをテストし,修正する可能性がある.
主な方法:
- 候補銀河の初期識別のために非常に深い近赤外線調査を使用した.
- 赤偏移と恒星の質量を確認するために 観測を行った.
- 現在の恒星形成活動を評価し,銀河の年齢を導き出すために吸収線スペクトルを分析した.
主要な成果:
- 光譜学的に,赤偏移 z = 3.717 で,太陽質量1.7 × 10 ^ 11 の恒星質量を持つ巨大な静止銀河が確認されました.
- 銀河の年齢は その時代の宇宙の年齢の半分近くで 現在の星形成の兆候はありません
- 宇宙の歴史の最初の10億年以内に 極端な星爆発によって 星の大半が急速に形成されたと推論した.
結論:
- この巨大で静止している銀河の存在は z=3.717 で,現在のモデルで予測されるよりもはるかに早く重要な銀河の集まりが起こったことを示しています.
- このような銀河の形成に必要な 急速な初期の星爆発は 初期の銀河の形成過程に対する 我々の理解を 挑戦しています
- これらの発見は,初期の宇宙における巨大な銀河の集合を記述する理論的枠組みの大幅な修正を必要とします.
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