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Updated: May 5, 2026
11:34
Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
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金属が少ない銀河の塵の希少さ
David B Fisher1, Alberto D Bolatto2, Rodrigo Herrera-Camus2
11] Department of Astronomy, Laboratory for Millimeter-wave Astronomy and Joint Space Institute, University of Maryland, College Park, Maryland 20742, USA [2] Centre for Astrophysics and Supercomputing, Swinburne University, PO Box 218, Hawthorn, Victoria 3122, Australia.
Nature
|December 10, 2013
まとめ
ヒミコ (z = 6.6) のような初期の銀河は,恒星形成に不可欠な冷たい塵をめったに示さない. 局所アナログ銀河I Zwicky 18の観測は,非常に低い塵対ガス比を明らかにし,初期の銀河はこれまで考えられていたよりもさらに少ない塵を持っている可能性があることを示唆しています.
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
- アストロケミストリー アストロケミストリー
背景:
- 赤道偏移 z > 6 (宇宙の年齢は10億年未満) の銀河は,めったに冷たい塵を示さない.
- 寒い塵は,局所宇宙の星形成の重要な構成要素である.
- 局所宇宙における塵とガスの質量比は,約1%である.
研究 の 目的:
- 原始的な銀河の塵の含有量を調査するために.
- 局所的矮星銀河I Zwicky 18 (I Zw18) を,高赤偏移の銀河のアナログとして使用する.
- 初期の恒星形成銀河の塵の性質を制限するために.
主な方法:
- I Zwicky 18からの塵の放射の観測
- 塵の質量と比率をI Zw18.で測定する
- I Zw18の性質を,ヒミコのような赤道偏移が大きい銀河と比較する.
主要な成果:
- I Zw18における塵の質量は,太陽の質量450~1800個と決定された.
- I Zw18における塵と恒星の質量比は ~10−6から10−5.5である.
- I Zw18における塵とガスの質量比は3.213 × 10−6で,局所宇宙よりもかなり低い.
結論:
- I Zw18は,潜在的なアナログとして,ヒミコの塵の質量は,上限より100倍低い約50,000太陽質量である可能性があることを示唆しています.
- ほとんどの高-z銀河がヒミコに似ているなら,それらの中のガスと塵を検出することは,予想以上に難しいかもしれません.
- 原始的な銀河は,局所銀河よりも塵の含有量がかなり低い可能性があり,初期の恒星形成モデルに影響を与えます.
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