arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.12222astro-ph.CO
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利用普朗克2018年数据在$Λ$ CDM以外的模型中扩展再电离

Extended reionization in models beyond $Λ$CDM with Planck 2018 data

Daniela Paoletti, Dhiraj Kumar Hazra, Fabio Finelli, George F. Smoot

摘要:

我们提供了普朗克2018年宇宙微波背景各向异性数据对扩展再电离历史的约束的更新。普朗克2018年大角度尺度的数据改进了低多极下$E$模式极化再电离凸起的测量,为改进我们以前的结果提供了可能性。通过对再电离历史的原始Poly-reion模型进行微小修改,我们发现普朗克2018年的数据显着改善了我们之前的所有结果:我们发现$τ=0.0572_{-0.0075}^{+0.0064}$在68%CL时的光学深度强烈不利于再电离的早期开始,即当再电离开始时红移,$z_{xe=0}=18.18_{-10.89}^{+1.61}$在68%CL时,再电离持续时间(定义为10%-99%再电离)显著减少,即$Δ_z^{Reion}=4.59_{-2.45}^{+1.67}$为68% CL。我们探讨了再电离历史和宇宙学参数之间可能的相关性,包括$Λ$ CDM之外的重要扩展。我们发现,再电离与标量谱指数、中微子质量和、空间曲率、暗物质湮灭等非标准模型之间的简并度显著降低,误差条的降低和简并度的降低,以及我们在Poly-reion模型中观察到的光学深度向低值的转变,主要是由新的低-基于HFI数据的普朗克2018年基线的$\ell$极化可能性。这一点也得到了在没有这种可能性的情况下得出的结果以及为一个模型子集提供的基线替代品不同的结果的证实。

英文摘要:

We provide an update on the constraints on extended reionization histories with the Planck 2018 cosmic microwave background anisotropy data. The Planck 2018 data on large angular scales improve the measurement of the $E$-mode polarization reionization bump at low multipoles providing the possibility to improve our previous results. Using a minor modification to the original Poly-reion model for the reionization history, we find that the Planck 2018 data significantly improve all our previous results: we find as optical depth of $τ=0.0572_{-0.0075}^{+0.0064}$ at 68% CL, that early onsets of reionization are strongly disfavoured, i.e. redshift when the reionization begins, $z_{xe=0}=18.18_{-10.89}^{+1.61}$ at 68% CL,and that reionization duration (defined between 10% and 99% reionization) is significantly reduced, i.e. $Δ_z^{Reion}=4.59_{-2.45}^{+1.67}$ at 68% CL. We explore possible correlations between reionization histories and cosmological parameters, including important extensions beyond $Λ$CDM. We find that the degeneracy between reionization and scalar spectral index,neutrino mass sum, spatial curvature, dark matter annihilation and other non-standard models are significantly reduced.The reduction of the error bars and the degeneracies, together with the shift towards lower values of the optical depth that we observe in the Poly-reion model are mainly driven by the new low-$\ell$ polarization likelihood of Planck 2018 baseline based on the HFI data. This is confirmed also by the results derived without this likelihood and the ones with different alternatives to the baseline that are presented for a subset of models.

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