Was the Universe Reionized by Massive Metal-free Stars?
Was the Universe Reionized by Massive Metal-free Stars?
复制标题
宇宙是否被大量无金属恒星重新电离？
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
A. Loeb
中科院分区：
文献类型：
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作者：
S. Wyithe;A. Loeb
威尔金森微波各向异性探测器卫星测量到宇宙复合后电子散射的大光学深度为τes = 0.17 ± 0.04，这意味着大爆炸后约2亿年原始气体发生了显著的再电离。然而，根据Lyα森林对星系际介质热历史的约束，星系际H II区最近的重叠一定发生在z 109。在这里，我们认为，第一代的无金属恒星的重（而不是萨尔彼得）的质量函数，因此需要占大部分的推断光学深度。如果反馈调节星星的形成在早期的矮星系中观察到今天的矮星。
The Wilkinson Microwave Anisotropy Probe satellite has measured a large optical depth to electron scattering after the cosmological recombination of τes = 0.17 ± 0.04, implying significant reionization of the primordial gas only ~200 million years after the big bang. However, the most recent overlap of intergalactic H II regions must have occurred at z ≲ 9 based on the Lyα forest constraint on the thermal history of the intergalactic medium. Here we argue that a first generation of metal-free stars with a heavy (rather than Salpeter) mass function is therefore required to account for much of the inferred optical depth. This conclusion holds if feedback regulates star formation in early dwarf galaxies as observed in present-day dwarfs.