A dust-obscured massive maximum-starburst galaxy at a redshift of 6.34
A dust-obscured massive maximum-starburst galaxy at a redshift of 6.34
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DOI：
10.1038/nature12050
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发表时间：
2013-04
期刊：
影响因子：
64.8
通讯作者：
D. Riechers;D. Riechers;C. Bradford;C. Bradford;D. Clements;C. Dowell;C. Dowell;I. Pérez-Fournon-I.-Pérez-Fourn
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文献类型：
--
作者：
D. Riechers;D. Riechers;C. Bradford;C. Bradford;D. Clements;C. Dowell;C. Dowell;I. Pérez-Fournon-I.-Pérez-Fourn
今天的大质量早期类型(椭圆形和透镜状)星系可能是通过早期最大质量的暗物质光晕中强烈的尘埃覆盖的星暴-即恒星形成速度的增加-获得了大部分恒星质量和重元素。然而，大爆炸过后多长时间内仍不清楚巨型恒星爆发的先驱者的存在。长期以来，由于选择效应，观测到的尘埃、大质量恒星爆发的红移(Z)分布一直被怀疑是有偏低的，最近红移高达∼5的系统的发现证实了这一点(参考文献)。在这里，我们报告了通过亚毫米颜色选择技术识别出一个质量为atz=6.34的星暴星系。我们毫不含糊地确定了一组分子和原子精细结构冷却线的红移。这些测量揭示了这个星系中有1000亿个太阳质量的高度激发的、化学演化的星际介质，它至少占重子质量的40%。“最大星暴”将气体转化为恒星的速度是银河系的2,000多倍，这是任何时期观测到的最高速度之一。尽管宇宙恒星的形成总体上朝着最高的红移低迷，但似乎成熟到足以形成最大质量、最强烈的星暴的环境至少早在大爆炸后8.8亿年就存在了。
Massive present-day early-type (elliptical and lenticular) galaxies probably gained the bulk of their stellar mass and heavy elements through intense, dust-enshrouded starbursts—that is, increased rates of star formation—in the most massive dark-matter haloes at early epochs. However, it remains unknown how soon after the Big Bang massive starburst progenitors exist. The measured redshift (z) distribution of dusty, massive starbursts has long been suspected to be biased low inzowing to selection effects, as confirmed by recent findings of systems with redshifts as high as ∼5 (refs ). Here we report the identification of a massive starburst galaxy atz= 6.34 through a submillimetre colour-selection technique. We unambiguously determined the redshift from a suite of molecular and atomic fine-structure cooling lines. These measurements reveal a hundred billion solar masses of highly excited, chemically evolved interstellar medium in this galaxy, which constitutes at least 40 per cent of the baryonic mass. A ‘maximum starburst’ converts the gas into stars at a rate more than 2,000 times that of the Milky Way, a rate among the highest observed at any epoch. Despite the overall downturn in cosmic star formation towards the highest redshifts, it seems that environments mature enough to form the most massive, intense starbursts existed at least as early as 880 million years after the Big Bang.