论文标题
用lyman- $α$发射器在z = 5.7处进行限制的电源:空隙,峰和宇宙差异
Constraining Reionization in Progress at z=5.7 with Lyman-$α$ Emitters: Voids, Peaks, and Cosmic Variance
论文作者
论文摘要
许多独立的观察表明,播放培养基在$ z = 7 $时显着中立,并且可能仍在$ z = 5.7 $的情况下进行回报。 SilverRush的窄带调查已在这些红移中绘制了超过$ 2,000 $ lyman-$α$发射器(Laes)。先前的分析假设电回离已经结束了$ z = 5.7 $,但是当将最后一个中性岛屿降级到宇宙空隙时,这些数据实际上可能采样了电离的最后阶段。在这些事态发展的驱动下,我们重新检查了LAE和峰值统计数据及其限制电离的能力。我们在(1 GPC $/h $)$^3 $卷中构建LAE分布的模型,涵盖了$ z = 5.7 $和6.6的一系列中性分数。中性分数较高的模型显示出在LAE分布中找到孔的可能性增强。但是,在比较固定平均表面密度的模型时,必须通过其他地方可见的Laes补偿了在空隙中被中性气所遮盖的LAE。因此,在这些模型中,在电离的后半段,发现过度密度峰的可能性也会增强。与广泛使用的角度的两点相关函数(2PCF)相比,我们发现在电离后半段期间,空隙概率函数(VPF)提供了模型的更敏感测试。相比之下,在中性分数$ \ sim 50 \%$,VPF和简单的峰值阈值统计量都与2PCF相似,在约束功率方面。最后,我们发现在Silverrush场中观察到的宇宙方差和大规模的不对称性与$λ$ CDM宇宙中的大规模结构一致。
A number of independent observations suggest that the intergalactic medium was significantly neutral at $z=7$ and that reionization was, perhaps, still in progress at $z=5.7$. The narrowband survey, SILVERRUSH, has mapped over $2,000$ Lyman-$α$ emitters (LAEs) at these redshifts. Previous analyses have assumed that reionization was over by $z=5.7$, but this data may actually sample the final stages of reionization when the last neutral islands were relegated to the cosmic voids. Motivated by these developments, we reexamine LAE void and peak statistics and their ability to constrain reionization. We construct models of the LAE distribution in (1 Gpc$/h$)$^3$ volumes, spanning a range of neutral fractions at $z=5.7$ and 6.6. Models with a higher neutral fraction show an enhanced probability of finding holes in the LAE distribution. When comparing models at fixed mean surface density, however, LAEs obscured by neutral gas in the voids must be compensated by visible LAEs elsewhere. Hence, in these models the likelihood of finding an over-dense peak is also enhanced in the latter half of reionization. Compared to the widely used angular two-point correlation function (2PCF), we find that the void probability function (VPF) provides a more sensitive test of models during the latter half of reionization. By comparison, at neutral fractions $\sim 50\%$, the VPF and a simple peak thresholding statistic are both similar to the 2PCF in constraining power. Lastly, we find that the cosmic variance and large-scale asymmetries observed in the SILVERRUSH fields are consistent with large-scale structure in a $Λ$CDM universe.