一个星系在红移7.51的大爆炸后7亿年迅速形成恒星
S L Finkelstein1, C Papovich, M Dickinson
1The University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, Texas 78712, USA.
Nature
|October 25, 2013
概括
天文学家调查了高红移 (z > 6.5) 的星系. 检测到一个红移z = 7.51的单个星系,显示了快速丰富和高恒星形成率,表明早期恒星形成比预期更为强烈.
科学领域:
- 太空进化的宇宙进化
- 银河系的形成和进化
- 早期宇宙天体物理学 天体物理学
背景情况:
- 由于莱曼α辐射检测,对红移 (z) > 7的星系进行光谱确认是具有挑战性的.
- 之前的研究表明,在z>6.5时,星系间介质中性分数的快速增加,阻碍了莱曼α检测.
- 在先前的研究中,有限的样本大小和观察深度使得结论暂时.
研究的目的:
- 为了对高红移量星系 (z > 6.5) 进行近红外深度光谱调查.
- 为了研究早期宇宙中莱曼α辐射的可检测性.
- 描述早期星系的特性,包括它们的金属含量和恒星形成率.
主要方法:
- 对43个光度学选择的星系进行了深度近红外光谱调查,z>6.5.5.
- 分析了排放线,以确认红移并确定莱曼α排放.
- 计算了星系的颜色,金属含量和恒星形成率.
主要成果:
- 检测到一个单一的星系与莱曼α发射线在红移z=7.51 (大爆炸后7亿年).
- 银河系呈现出与大量金属丰富相一致的颜色,表明银河系的快速演变.
- 计算出每年约有330个太阳质量的恒星形成率,是银河系的100倍以上.
结论:
- 证实莱曼α辐射很难在早期宇宙中检测到,可能是由于星系间介质的特性.
- 表明星系在早期宇宙中经历了快速的化学丰富.
- 表明早期宇宙可能包含比以前预期的更强烈的恒星形成区域.
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