原始銀河の重力崩壊によって形成された非常に若い巨大な塊
A Zanella1, E Daddi1, E Le Floc'h1
1Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Université Paris Diderot, Irfu/Service d'Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif sur Yvette, France.
Nature
|May 8, 2015
まとめ
天文学者は,遠くの銀河で巨大な若い恒星形成の塊を観測し,塊形成の最初の直接的な証拠を提供しました. これらの塊は,銀河がどのように中央の膨らみを形成するのかを理解するために重要である.
科学分野:
- 銀河系の進化について.
- 星形成 星形成について
- 天体物理学 天体物理学
背景:
- 恒星形成のピーク (赤道偏移 z ≈ 2) の銀河は,巨大な塊を持つガスに富んだ円盤を特徴としています.
- 塊の形成は,渦巻円盤の重力不安定性によって発生すると理論化されています.
- これらの塊の生存と膨らみ形成の役割は依然として議論の余地があります.
研究 の 目的:
- 銀河団形成イベントを観察し,特徴づけること.
- 若い,巨大な塊の性質と恒星形成の効率を調査する.
- 銀河の膨らみ形成における塊の役割を評価する.
主な方法:
- z = 1.987.7の銀河の非核放射線領域の空間的に解明されたスペクトルスコピー.
- 恒星連続体を検出するための深層画像.
- 水力力学シミュレーションとの比較.
主要な成果:
- 極めて若い (<1000万年) 巨大な塊 (>10億太陽質量) を直接観測した.
- この塊は,宿主銀河の円盤の恒星形成を支配している.
- ガス消費率が10倍高く,恒星形成の効率が高かったことが観測されました.
結論:
- 銀河団の結集形成に関する最初の観測証拠を提供する.
- 群が恒星のフィードバックを生き延び,膨張の成長に貢献するモデルをサポートします.
- 銀河団の寿命が長い (約5億年) と,銀河系の進化における重要な役割を示唆している.
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