The Clustering Properties of Lyman Break Galaxies at Redshift z ~ 3
The Clustering Properties of Lyman Break Galaxies at Redshift z ~ 3
复制标题
莱曼断裂星系在红移 z ~ 3 处的聚类特性
DOI：
10.1086/324198
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
M. Giavalisco
中科院分区：
文献类型：
--
作者：
C. Porciani;M. Giavalisco
我们提出了莱曼断裂星系 (LBG) 在 z ~ 3 处的角度两点相关函数的新测量方法，该函数是从二维单元中星系计数的方差获得的。通过避免角度间隔的合并，与传统测量方法相比，该方法受散粒噪声的影响明显较小，并且可以更准确地确定相关函数。我们使用了 Steidel 和合作者从调查中提取的约 1000 个 ℛ ≤ 25.5 星系的样本，得出了以下结果。在 30′′ ≲ θ ≲ 100′′ 范围内的尺度下，角度相关函数 w(θ) 可以准确地描述为斜率 β = 0.50（1 σ 随机）-0.10（系统）的幂律，比 Giavalisco 及其合作者提出的测量更浅。然而，由 Limber 反投影得出的空间相关长度与之前的测量结果非常一致，证实了这些源的强空间聚集性。我们详细讨论了随机误差和系统误差的影响，特别是所谓的积分约束偏差，我们使用数值模拟设置了下限。这表明当前样本尚未提供 LBG 在 z ~ 3 处的大规模分布的“公平表示”。我们分析的一个有趣结果是，在角间距小于 θ ≲ 30′′ 时，相关函数似乎偏离了在较大尺度上拟合的幂律并变得更小。该特征的检测可信度约为 90%，如果真实，可以提供有关其宿主光环内 LBG 的数量密度和空间分布以及光环的大小和质量的信息。
We present a new measure of the angular two-point correlation function of Lyman break galaxies (LBGs) at z ~ 3, obtained from the variance of galaxy counts in two-dimensional cells. By avoiding binning of the angular separations, this method is significantly less affected by shot noise than traditional measures and allows for a more accurate determination of the correlation function. We used a sample of about 1000 galaxies with ℛ ≤ 25.5 extracted from the survey by Steidel and collaborators and found the following results. At scales in the range 30′′ ≲ θ ≲ 100′′, the angular correlation function w(θ) can be accurately described as a power law with slope β = 0.50 (1 σ random)-0.10 (systematic), shallower than the measure presented by Giavalisco and collaborators. However, the spatial correlation length, derived by Limber deprojection, is in very good agreement with the previous measures, confirming the strong spatial clustering of these sources. We discuss in detail the effects of both random and systematic errors, in particular of the so-called integral constraint bias, to which we set a lower limit using numerical simulations. This suggests that the current samples do not yet provide a "fair representation" of the large-scale distribution of LBGs at z ~ 3. An intriguing result of our analysis is that at angular separations smaller than θ ≲ 30′′ the correlation function seems to depart from the power law fitted at larger scales and become smaller. This feature is detected at the ~90% confidence level and, if real, can provide information on the number density and spatial distribution of LBGs within their host halos as well as the size and the mass of the halos.