クエーサールに隣接する高速に恒星を形成する銀河は,赤道偏移が6を超えている
R Decarli1, F Walter1,2,3, B P Venemans1
1Max Planck Institut für Astronomie, Königstuhl 17, Heidelberg 69117, Germany.
Nature
|May 26, 2017
まとめ
巨大な初期の銀河には 恒星形成の速度は高い必要があります 天文学者はクエーサーの近くで4つの銀河を発見し,赤道偏移 z > 6で,恒星形成率は年間100太陽質量以上で,銀河の進化のヒントを提供します.
科学分野:
- 宇宙の進化
- 銀河の形成と進化
- 初期の宇宙の天体物理学
背景:
- z ≈ 4 の巨大な円銀河は,初期の宇宙 (z > 6) で高い恒星形成率を暗示しています.
- これまでの調査では この初期の時代に 十分な恒星形成率を持つ銀河はほとんど見つかりませんでした
- クワザール宿主銀河は,z > 6で非常に高い恒星形成率を持つ唯一の既知のソースですが,活発な超大質量ブラックホールをホストしています.
研究 の 目的:
- z > 6で恒星形成率が高い銀河の存在と性質を調査する.
- 後に観測された巨大な円銀河の潜在的祖先を特定する.
- 超大質量ブラックホールが 活発に成長していない 恒星形成率が高い銀河を探します
主な方法:
- 158ミクロメートルの単離炭素 ([C ii]) 放射線の観測.
- 近くにある銀河 (速度<600 km/s,線形偏差<100 kpc) をターゲットにします.
- 偶然の発見のための 遠赤外線照明の選択
主要な成果:
- 4つの伴星銀河から z > 6個のクエザールへの[C ii]放射の検出
- これらの伴星銀河の恒星形成の割合は 年間100太陽質量を超えています
- これらの伴星銀河は,クワザーの宿主銀河と類似した[C ii]の明るさ,線幅,動的質量を示しているが,活発な超大質量ブラックホールの証拠はない.
結論:
- この研究は,クエーザーの宿主ではない,z > 6の高い恒星形成率を持つ銀河群を特定した.
- これらの伴星系は, z ≈ 4 で観測された巨大な円銀河の祖先である可能性があります.
- 観測された25個のクエーザーのうち4つのクエーザーの存在率は,銀河形成の理論モデルに組み込まれる必要がある.
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