论文标题
物质的速度曲线和偏见的示踪剂周围的空隙
Velocity profiles of matter and biased tracers around voids
论文作者
论文摘要
空隙周围星系的速度曲线是使用void-galaxy相关函数进行的红移空间失真（RSD）测量的关键要素。在本文中，我们使用模拟来测试用于找到空隙的示踪剂的速度曲线是否与这些空隙周围暗物质的速度曲线相匹配。预期并在空隙的内部发现了不匹配，那里的示踪剂非常稀疏。我们讨论了这种差异是由选择效应引起的，其中空隙中心位置与稀疏示踪剂及其空间分布的特殊实现相关。反过来，这会影响RSD空隙 - 摩乳相关分析。我们通过评估使用示踪剂或物质速度配置文件的真实的雅各比式来映射真实的雅各布式。速度曲线中20 \％的差异的差异转化为雅各布式中几个百分比的差异。这种小的差异传播到了void-tracer相关函数的单子和四极杆，从而在当前分析的统计不确定性级别上产生了与$fσ_8$变化的变化相当的修改。
The velocity profile of galaxies around voids is a key ingredient for redshift space distortion (RSD) measurements made using the void-galaxy correlation function. In this paper we use simulations to test whether the velocity profile of the tracers used to find the voids matches the velocity profile of the dark matter around these voids. A mismatch is expected and found in the inner part of voids, where tracers are very sparse. We discuss how this difference is caused by a selection effect where the void centre positions are correlated to the particular realization of the sparse tracers and their spatial distribution. In turn, this then affects the RSD void-galaxy correlation analysis. We show this by evaluating the Jacobian of the real to redshift space mapping using the tracer or matter velocity profile. Differences of the order of 20\% in the velocity profile translate into differences of the order of few percent in the Jacobian. This small discrepancy propagates to the monopole and quadrupole of the void-tracer correlation function, producing modifications of comparable magnitude to those from changes in $fσ_8$ at the level of the statistical uncertainties from current analyses.
