论文标题
偏见现象
Biasing phenomenon
论文作者
论文摘要
我们通过分析模拟星系样品和暗物质（DM）样品的功率谱（PS）和相关函数（CF）来研究偏见。我们使用具有$ρ\ geρ_0$的粒子的粒子，基于粒子$ρ$的局部密度来应用算法。我们计算了针对各种粒子密度限制$ρ_0$的模拟星系的投影（2D）和空间（3D）密度字段的两点CF。我们比较3D和2D CFS；在2D情况下，我们使用各种厚度的样品来找到2D CFS对样品厚度的依赖性。宇宙网络的主要元素是簇和细丝，由填充大部分体积的空隙隔开。在单独的2D纸片中，簇和细丝的位置不一致。结果，投影簇和细丝填充了2D空隙。这导致CFS投影中CF的振幅减少。因此，2D CFS的幅度低于3D CFS的振幅，差异较大，较厚的是2D样品。使用模拟星系和DM的PS和CF，我们估计$ l^\ ast $ Galaxies的偏差因子，$ b^\ ast = 1.85 \ pm 0.15 $。
We study biasing as a physical phenomenon by analysing power spectra (PS) and correlation functions (CF) of simulated galaxy samples and dark matter (DM) samples. We apply an algorithm based on the local densities of particles, $ρ$, to form populations of simulated galaxies, using particles with $ρ\ge ρ_0$. We calculate two-point CF of projected (2D) and spatial (3D) density fields of simulated galaxies for various particle-density limits $ρ_0$. We compare 3D and 2D CFs; in 2D case we use samples of various thickness to find the dependence of 2D CFs on thickness of samples. Dominant elements of the cosmic web are clusters and filaments, separated by voids filling most of the volume. In individual 2D sheets positions of clusters and filaments do not coincide. As a result, in projection clusters and filaments fill in 2D voids. This leads to the decrease of amplitudes of CFs in projection. For this reason amplitudes of 2D CFs are lower than amplitudes of 3D CFs, the difference is the larger, the thicker are 2D samples. Using PS and CFs of simulated galaxies and DM we estimate the bias factor for $L^\ast$ galaxies, $b^\ast =1.85 \pm 0.15$.
