论文标题
Z = 5.7的原始群体：从Multidark Galaxies的视图
Protoclusters at z=5.7: A view from the MultiDark galaxies
论文作者
论文摘要
将在较低的红移下产生星系簇的原始群体可以提供有关星系簇形成的宝贵信息。但是，在观测中识别星系簇的祖细胞并不是一件容易的事，尤其是在高红移时。已使用不同的先验来估计被认为标志着原群体位置的过度密度区域。在本文中，我们使用$ z = 5.7 $的模仿$α$发射星系来识别Multidark Galaxies中的Prodoclusters，通过将三种不同的半分析模型应用于1 $ GPC H^{-1} $ Multidark Planck2 Simulation。为了与观察结果进行比较，我们将标准1（$ ly $α$光度限制样本）扩展到标准2（与观察到的平均星系数密度匹配）。为了进一步研究这种方法的发现效率，我们将确定的原始样品（标准3）扩大到约3500 $ z = 5.7 $，并研究其最终质量分布。过度密度区域及其选择概率的数量取决于半分析模型，并且强烈地取决于三个选择标准（部分按设计）。具有标准1识别的原始群体与典型的最终集群质量为$ 2.82 \ pm0.92 \ times 10^{15} m_ \ odot $，与预测（$ \ pm1σ$）一致（在$ \ pm1σ$之内），该预测量为$ z = 5.7 $。识别更多的原始群体使我们能够研究此方法的效率，该方法更适合识别最大的簇：完整性（$ \ Mathbb {c} $）随着晕光质量的降低而迅速下降。我们进一步发现，很难同时具有高纯度（$ \ mathbb {p} $）和完整性。
Protoclusters, which will yield galaxy clusters at lower redshift, can provide valuable information on the formation of galaxy clusters. However, identifying progenitors of galaxy clusters in observations is not an easy task, especially at high redshift. Different priors have been used to estimate the overdense regions that are thought to mark the locations of protoclusters. In this paper, we use mimicked Ly$α$-emitting galaxies at $z=5.7$ to identify protoclusters in the MultiDark galaxies, which are populated by applying three different semi-analytic models to the 1 $Gpc h^{-1}$ MultiDark Planck2 simulation. To compare with observational results, we extend the criterion 1 (a Ly$α$ luminosity limited sample), to criterion 2 (a match to the observed mean galaxy number density). To further statistically study the finding efficiency of this method, we enlarge the identified protocluster sample (criterion 3) to about 3500 at $z=5.7$ and study their final mass distribution. The number of overdense regions and their selection probability depends on the semi-analytic models and strongly on the three selection criteria (partly by design). The protoclusters identified with criterion 1 are associated with a typical final cluster mass of $2.82\pm0.92 \times 10^{15} M_\odot$ which is in agreement with the prediction (within $\pm 1 σ$) of an observed massive protocluster at $z=5.7$. Identifying more protoclusters allows us to investigate the efficiency of this method, which is more suitable for identifying the most massive clusters: completeness ($\mathbb{C}$) drops rapidly with decreasing halo mass. We further find that it is hard to have a high purity ($\mathbb{P}$) and completeness simultaneously.
