赤道偏移5〜6の銀河は,一貫して塵の含有量が低く,[C II]の放出量が高い
P L Capak1, C Carilli2, G Jones3
11] Infrared Processing and Analysis Center (IPAC), 1200 East California Boulevard, Pasadena, California 91125, USA [2] California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.
Nature
|June 26, 2015
まとめ
初期の銀河 (赤道偏移 z > 4) は,後の宇宙時代と比較して,塵がかなり少なく,二酸化炭素の放出が増加しています. これは,若い宇宙に急速に進化する星間媒体が存在していたことを示唆している.
科学分野:
- 宇宙の進化とは,宇宙の進化である.
- 銀河の形成と進化について
- 星間媒体の特性
背景:
- 赤道偏移 z > 4 時の銀河の紫外線の性質は,急速な塵の遮蔽の進化を示唆しています.
- 初期の銀河における星間媒体の以前の測定は,仮定と検出能力によって制限されていました.
研究 の 目的:
- 初期の恒星形成銀河の恒星間媒体の特性を直接測定するために.
- ビッグバン (z ≈ 5−6) から約10億年後の銀河の塵とガスの含有量を調査する.
主な方法:
- ガスから測定された禁止炭素II ([CII]) 排出量.
- z ≈ 5-6の9つの典型的な恒星形成銀河の塵からの遠赤外線放射を測定しました.
主要な成果:
- これらの初期の銀河は,後の時期 (z < 3) の類似の銀河の1 / 12未満の熱放出を示しています.
- 遠赤外線連続体に対する強化された[C II]放射は,異なるガスと塵の比率を示している.
- ガスは,様々なダイナミクスを持つ1〜8キロパーセックに分布しています.
結論:
- 初期の銀河の星間介質は大きく進化し,z < 3の銀河よりも塵がかなり少なくなった.
- これらの初期の銀河の塵の含有量は,局所的な低金属性のシステムに匹敵する.
- これらの発見は,初期の銀河の構成と進化に関する以前の仮定に異議を唱える.
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