论文标题
偏见的时间演变
The time evolution of bias
论文作者
论文摘要
我们研究了宇宙密度场偏置的时间演变。我们对常规$λ$冷暗物质（$λ$ cdm）模型进行宇宙网络演变的数值模拟。模拟涵盖了各种盒子尺寸$ l = 256-1024 \ mpc $，以及从很早的矩$ z = 30 $到现在的时刻$ z = 0 $。我们使用有偏见的$λ$ CDM模拟的暗物质颗粒计算星系的空间相关函数，$ξ（r）$。我们分析了这些功能如何描述不断发展的宇宙网络的偏置特性。我们发现，对于所有宇宙时期，通过选定样品和物质的相关函数的比率定义的偏差参数取决于两个因素：空隙中的物质和群集种群中的物质分数，以及星系样品的亮度（质量）。重力不能完全撤离空隙，因此在整个演化时期，星系中总是有一些未聚集的物质，因此星系的偏置参数总是大于统一。我们发现，对于所有宇宙时期的偏置参数值构成常规序列，具体取决于星系光度（粒子密度极限），并且随时间而减小。
We investigate the time evolution of bias of cosmic density fields. We perform numerical simulations of the evolution of the cosmic web for the conventional $Λ$ cold dark matter ($Λ$CDM) model. The simulations cover a wide range of box sizes $L=256 - 1024\Mpc$, and epochs from very early moments $z=30$ to the present moment $z=0$. We calculate spatial correlation functions of galaxies, $ξ(r)$, using dark matter particles of the biased $Λ$CDM simulation. We analyse how these functions describe biasing properties of the evolving cosmic web. We find that for all cosmic epochs the bias parameter, defined through the ratio of correlation functions of selected samples and matter, depends on two factors: the fraction of matter in voids and in the clustered population, and the luminosity (mass) of galaxy samples. Gravity cannot evacuate voids completely, thus there is always some unclustered matter in voids, thus the bias parameter of galaxies is always greater than unity, over the whole range of evolution epochs. We find that for all cosmic epochs bias parameter values form regular sequences, depending on galaxy luminosity (particle density limit), and decreasing with time.
