Spectroscopic confirmation of a galaxy at redshift z = 8.6.
Spectroscopic confirmation of a galaxy at redshift z = 8.6.
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红移 z = 8.6 处星系的光谱确认。
DOI：
10.1038/nature09462
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发表时间：
2010
期刊：
影响因子：
64.8
通讯作者：
Lehnert MD
中科院分区：
文献类型：
--
作者：
Lehnert MD
当星系聚集了第一代恒星时，它们对宇宙的影响最为显著。原始星系中年轻的大质量恒星发出的高能光子电离了围绕其宿主星系的星系间介质，清除了年轻星系的光线可以逃逸的视线，并从根本上改变了宇宙中星系间气体的物理状态，直到今天。对宇宙微波背景，以及最高红移的星系和类星体的观测表明，宇宙是通过一个复杂的过程再电离的，这个过程是在大爆炸后大约10亿年完成的，红移系数≈6。探测来自越来越遥远的星系的电离莱曼α光子，对再电离源的时间、位置和性质都有重要的限制。在这里，我们报告了在大爆炸后不到6亿年发射的Lyα光子的探测。UDFy-38135539（参考文献）的红移为z= 8.5549±0.0002，这比之前已知的最远天体的红移要大，atz= 8.2（参考文献和）和z= 6.96（参考文献）。我们发现，这个单一的光源不太可能提供足够的光子来电离发射线逃逸所必需的体积，这需要附近其他可能更暗淡的星系的大量贡献。
Galaxies had their most significant impact on the Universe when they assembled their first generations of stars. Energetic photons emitted by young, massive stars in primeval galaxies ionized the intergalactic medium surrounding their host galaxies, cleared sightlines along which the light of the young galaxies could escape, and fundamentally altered the physical state of the intergalactic gas in the Universe continuously until the present day,. Observations of the cosmic microwave background, and of galaxies and quasars at the highest redshifts, suggest that the Universe was reionized through a complex process that was completed about a billion years after the Big Bang, by redshiftz≈ 6. Detecting ionizing Lyman-α photons from increasingly distant galaxies places important constraints on the timing, location and nature of the sources responsible for reionization. Here we report the detection of Lyα photons emitted less than 600 million years after the Big Bang. UDFy-38135539 (ref. ) is at a redshift ofz= 8.5549 ± 0.0002, which is greater than those of the previously known most distant objects, atz= 8.2 (refs and ) andz= 6.96 (ref. ). We find that this single source is unlikely to provide enough photons to ionize the volume necessary for the emission line to escape, requiring a significant contribution from other, probably fainter galaxies nearby.