Cosmic reionization after Planck
Cosmic reionization after Planck
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DOI：
10.1093/mnrasl/slv134
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发表时间：
2015-05
影响因子：
4.8
通讯作者：
Sourav Mitra;T. R. Choudhury;A. Ferrara
中科院分区：
文献类型：
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作者：
Sourav Mitra;T. R. Choudhury;A. Ferrara
宇宙再电离是理解宇宙结构形成的关键，它可以告诉我们第一源的性质，如它们的恒星形成效率和电离光子逃逸分数。通过结合最近发布的普朗克电子散射光学厚度数据和高红移类星体吸收光谱的观测，我们获得了对可行的再电离历史的强烈约束。我们表明，普朗克数据的包含有利于单个恒星群的再电离场景。平均x_(Rm)HI_$从$z=10.6$时的$sim0.8$下降到$z=5.8$时的$\sim10^-4}$，再电离在$5.8\less_z\less_(8.5)$(2-$\sigma$)附近完成，这表明高红移源对再电离的贡献显著减少。通过将高红移星系光度函数数据结合到我们的分析中，我们可以对电离光子的逃逸分数施加独立的约束。我们发现在红移范围$z=6-9$中有一个不演化的$f{\rm Esc}$。
Cosmic reionization holds the key to understand structure formation in the Universe, and can inform us about the properties of the first sources, as their star formation efficiency and escape fraction of ionizing photons. By combining the recent release of Planck electron scattering optical depth data with observations of high-redshift quasar absorption spectra, we obtain strong constraints on viable reionization histories. We show that inclusion of Planck data favors a reionization scenario with a single stellar population. The mean $x_{\rm HI}$ drops from $\sim0.8$ at $z=10.6$ to $\sim10^{-4}$ at $z=5.8$ and reionization is completed around $5.8\lesssim z\lesssim8.5$ (2-$\sigma$), thus indicating a significant reduction in contributions to reionization from high redshift sources. We can put independent constraints on the escape fraction $f_{\rm esc}$ of ionizing photons by incorporating the high-redshift galaxy luminosity function data into our analysis. We find a non-evolving $f_{\rm esc}$ of $\sim10\%$ in the redshift range $z=6-9$.