12 億 年 前 の 星爆発 銀河 の 引力 的 に 不安定 な ガス 円盤
K Tadaki1, D Iono2,3, M S Yun4
1National Astronomical Observatory of Japan, Tokyo, Japan. tadaki.ken@nao.ac.jp.
Nature
|August 31, 2018
まとめ
初期の宇宙の銀河は 凝縮され 塵に満ちた核心で 星を急速に形成しました 引力的に不安定で 1億年以内にガスを消費します
科学分野:
- 天文学と天体物理学
- 宇宙の進化
- 銀河の形成
背景:
- 初期の宇宙のサブミリメートル銀河は 銀河系より約1,000倍高い恒星形成率を示しています
- この恒星形成の重要な部分は,コンパクトで中央のキロパセック領域に集中しています.
- これらのコアの物理的および運動的性質を理解することは,高角解像度の必要性のために困難です.
研究 の 目的:
- 赤道偏移 z=4.3 で,サブミリメートルの明るい銀河の遮蔽された核内の分子ガスの空間的および運動的構造を調査する.
- これらのコンパクトなスターバーストコアのガスの円盤が 回転的に支えられ 重力的に不安定であるかどうかを決定します
- 初期の宇宙の星系における 恒星形成のガス消費時間尺度を推定する.
主な方法:
- z=4.3のレンズのない亜ミリメートル明るさの銀河のガスと塵の観測.
- 線形解像度550パーセックで 銀河の核を詳細に探査できる
- 面積単位あたりの質量と動力学 (回転速度対速度分散) を含む分子ガス特性分析.
主要な成果:
- 塵で覆われた原子核の 空間構造と運動構造を解明した
- ガスの円盤が塊状で,回転速度が分散速度を超えていることを実証した.
- 分析によると 星爆発円盤は重力的に不安定で 自重力が回転とフィードバック圧力を支配しています
結論:
- 観測された星爆発円盤の重力不安定は 恒星形成による急速なガス消費を示唆している.
- 分子ガスは,約1億年の時間スケールで消費されると予測されています.
- この急速な枯渇の時間スケールは 星爆発銀河の合体で観測された時間スケールに匹敵します
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