強力な活発な銀河核による恒星形成の抑制

M J Page¹, M Symeonidis, J D Vieira

¹Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK. mjp@mssl.ucl.ac.uk

Nature

|May 12, 2012

まとめ

銀河の巨大なブラックホールは,恒星形成を調節しているのかもしれない. 強力な活性銀河核 (AGN) は,宿主銀河の活発な恒星形成を抑制し,銀河の進化に影響を及ぼしているようです.

科学分野:

* 天体物理学
*銀河進化の進化について
* 宇宙学 (コスモロジー)

背景:

* 巨大なブラックホールや銀河の突起は,初期の宇宙史の遺物であり,高い恒星形成率を持っています.
* ブラックホールの質量と恒星の膨らみ質量の間には,おそらく恒星形成を抑制する活発な銀河核 (AGN) による疑わしいリンクが存在する.
*X線はAGNの明確なトレーサーであり,恒星形成銀河はしばしば塵で覆われ,赤外線/サブミリメートル波長で明るく輝きます.

研究の目的:

* 活発な銀河核 (AGN) と,初期の銀河における星形成の関係を調査する.
*AGN活動が宿主銀河の星形成を抑制するという仮説を検証する.

主な方法:

* 銀河の宿主銀河のサブミリメートルとX線観測を組み合わせた.
* 2~60億年の宇宙年齢の銀河におけるX線光度と恒星形成率の分析.

主要な成果:

* 急速な星形成は,宇宙が2~60億年前のとき,AGNの宿主銀河で一般的であった.
* ブラックホールの周りの活発な星形成が抑制され,X線光度が毎秒10~44エルグを超えた.
* 強力なAGNの宿主銀河では,恒星形成の明確な抑制が観察されています.

結論:

* 強力なAGN活動により,宿主銀河の星形成が停止しているようです.
* この抑制は,AGNのアウトフローが恒星間介質を放出し,銀河の特性を急速に変容させるモデルと一致しています.
*この発見は,銀河の進化を調節するAGNフィードバックの役割を裏付けている.

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