Conventional wisdom was that thermal relics from the epoch of reionization (EOR) would vanish swiftly and hence the usual intergalactic medium (IGM) temperature-density relation would be recovered rapidly. Thus the Ly$\alpha$ forest is one of the primary cosmological probes at the post-reionization epoch. Recently, however, it was shown that the imprint of cosmic reionization can survive to lower redshifts ($z \sim 2$) than previously thought. Given the high sensitivities of upcoming Ly$\alpha$ forest surveys, this effect will be a novel broadband systematic that must be tackled for cosmological application. From the astrophysical point of view, however, the imprint of inhomogeneous reionization can shed light on the EOR and cosmic dawn. We utilize a hybrid method --- which includes two different simulation codes capable of handling the huge dynamical range --- to show the impact of patchy reionization on the Ly$\alpha$ forest and its dependence on different astrophysical scenarios. We found small, but statistically significant, deviations in the 1D Ly$\alpha$ power spectrum that range from a tenth of per cent at $z = 2$ to a few per cent at $z = 4$. The deviations in the 3D Ly$\alpha$ power spectrum are considerably large and range from a few per cent at $z = 2$ up to tens of per cent at $z = 4$. By exploiting different $k$-dependence of power spectrum among various astrophysical scenarios, the effect of patchy reionization on the Ly$\alpha$ forest power spectrum can open a new window into the cosmic reionization and possibly even the cosmic dawn.

中文翻译：

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Lyα森林功率谱作为进入再电离和宇宙黎明时代的新兴窗口

传统观点认为，再电离时代 (EOR) 的热遗迹会迅速消失，因此通常的星系间介质 (IGM) 温度-密度关系将迅速恢复。因此，Ly$\alpha$ 森林是再电离后时代的主要宇宙学探测器之一。然而，最近表明，宇宙再电离的印记可以在比以前认为的更低的红移 ($z \sim 2$) 中存活下来。鉴于即将进行的 Ly$\alpha$ 森林调查的高度敏感性，这种效应将是一种新的宽带系统，必须在宇宙学应用中加以解决。然而，从天体物理学的角度来看，不均匀再电离的印记可以揭示 EOR 和宇宙黎明。我们利用一种混合方法——其中包括能够处理巨大动态范围的两种不同的模拟代码——来展示斑块再电离对 Ly$\alpha$ 森林的影响及其对不同天体物理场景的依赖。我们发现一维 Ly$\alpha$ 功率谱的偏差很小，但具有统计学意义，偏差范围从 $z = 2$ 的十分之一到 $z = 4$ 的几个百分点。3D Ly$\alpha$ 功率谱的偏差相当大，范围从 $z = 2$ 时的百分之几到 $z = 4$ 时的百分之几十。通过在各种天体物理场景中利用不同的 $k$ 功率谱依赖性，片状再电离对 Ly$\alpha$ 森林功率谱的影响可以打开一扇了解宇宙再电离甚至宇宙黎明的新窗口。