论文标题
拉格朗日空间中的红移空间扭曲和线性的大规模速度场
Redshift space distortions in Lagrangian space and the linear large scale velocity field of dark matter
论文作者
论文摘要
解开红移空间坐标之间的连接，速度测量和三维实际空间坐标，是一个宇宙学问题，通常是通过对速度位置耦合的线性理解来建模的。该线性信息可以更好地保存在物质密度字段的拉格朗日空间图片中。通过Lagrangian空间测量，我们可以提取更多信息，并对宇宙的线性增长率进行更准确的估计。在本文中，我们通过转移函数解决了物质粒子速度的线性建模，并在此过程中检查了与初始条件的相关性减少在多大程度上可能受到基于速度的非线性污染。通过对单极四极比率进行彻底的分析，我们找到了欧拉速度分散的最佳拟合值，$σ_p= 378.3 $ km/s/s/s的lorentzian of-of-of-of-of-of-of-of-of-of-od-fing of-od of-od of-od of-od fing of-od finger of-od finger of-od ting of-od fing of-od finger of-od ting damping damping因子和$σ_p= 254.6 $ km/s for Gaussian One。在欧拉和拉格朗日案件中估计宇宙线性增长率$ f $的协方差。比较Lagrangian和Eulerian，我们发现$ F $中的错误提高了3倍，而无需非线性速度分散模型。
Untangling the connection between redshift space coordinates, a velocity measurement, and three dimensional real space coordinates, is a cosmological problem that is often modeled through a linear understanding of the velocity-position coupling. This linear information is better preserved in the Lagrangian space picture of the matter density field. Through Lagrangian space measurements, we can extract more information and make more accurate estimates of the linear growth rate of the universe. In this paper, we address the linear modelling of matter particle velocities through transfer functions, and in doing so examine to what degree the decrease in correlation with initial conditions may be contaminated by velocity-based nonlinearities. With a thorough analysis of the monopole-quadrupole ratio, we find the best-fit values for the Eulerian velocity dispersion, $σ_p = 378.3$ km/s for a Lorentzian finger-of-God damping factor and $σ_p = 254.6$ km/s for a Gaussian one. The covariance of the cosmological linear growth rate $f$, is estimated in the Eulerian and Lagrangian cases. Comparing Lagrangian and Eulerian, we find that the error in $f$ improves by a factor of 3, without the need for nonlinear velocity dispersion modelling.
