The First Billion Years project: proto-galaxies reionizing the universe
The First Billion Years project: proto-galaxies reionizing the universe
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第一个十亿年项目：原星系重新电离宇宙
DOI：
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
C. D. Vecchia
中科院分区：
文献类型：
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作者：
J. Paardekooper;S. Khochfar;C. D. Vecchia
星系中恒星对宇宙再电离的贡献取决于宇宙中恒星的形成历史、再电离过程中星系的丰度、电离光子的逃逸分数和星际介质的聚集因子。我们利用高分辨率流体动力学模拟计算了宇宙体积中再电离过程中的恒星形成率和团簇因子。我们用详细的辐射传输模拟对输出进行后处理，以计算电离光子的逃逸分数。总而言之，这给了我们一个机会来评估星系对自我持续的再电离的贡献。逃逸分数与质量和红移的强烈依赖关系表明，再电离发生在z=15-10之间，主要是由质量在107-108M�之间的暗物质晕中形成的原星系驱动的。与更丰富的低质量星系相比，更多的大质量星系在红移时很少见，而且逃逸分数明显较低，对再电离过程贡献的光子更少。低质量晕中恒星的形成受到再电离辐射反馈的抑制，因此这些原星系只有在它们所在的宇宙部分仍然是中性的时候才会做出贡献。在∼10之后，大质量星系变得更加丰富，并提供了大部分电离光子。此外，我们发现第三族恒星的寿命太短，频率也不够高，不足以对电离有重大贡献。尽管在再电离过程中产生大量电离光子的原星系的恒星成分太弱，无法被JamesWebbSpaceTelescope探测到，但这些源在Hα和Lyα复合线上最亮，这可能会被JWST在深空探测中探测到。
The contribution of stars in galaxies to cosmic reionization depends on the star formation history in the Universe, the abundance of galaxies during reionization, the escape fraction of ionizing photons and the clumping factor of the intergalactic medium. We compute the star formation rate and clumping factor during reionization in a cosmological volume using a high-resolution hydrodynamical simulation. We post-process the output with detailed radiative transfer simulations to compute the escape fraction of ionizing photons. Together, this gives us the opportunity to assess the contribution of galaxies to reionization self-consistently. The strong mass and redshift dependence of the escape fraction indicates that reionization occurred between z = 15 and 10 and was mainly driven by proto-galaxies forming in dark matter haloes with masses between 10 7 and 10 8 M� . More massive galaxies that are rare at these redshifts and have significantly lower escape fractions contribute less photons to the reionization process than the more-abundant low-mass galaxies. Star formation in the low-mass haloes is suppressed by radiative feedback from reionization, therefore these proto-galaxies only contribute when the part of the Universe they live in is still neutral. Afterz ∼ 10, massive galaxies become more abundant and provide most of the ionizing photons. In addition, we find that Population III stars are too short-lived and not frequent enough to have a major contribution to reionization. Although the stellar component of the proto-galaxies that produce the bulk of ionizing photons during reionization is too faint to be detected by theJamesWebbSpaceTelescope (JWST), these sources are brightest in the Hα and Lyα recombination lines, which will likely be detected by JWST in deep surveys.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.