标题： 晕族成员在投影相空间中的普遍分布。 星系团浓度和速度各向异性中的偏差？ 显示英文标题

标题： The universal distribution of halo interlopers in projected phase space. Bias in galaxy cluster concentration and velocity anisotropy?

摘要： 当星系团在投影中被观测时，不可避免地会挑选出位于引力暴圈（VC）内但位于引力球面外的前景/背景闯入者。 对于一个膨胀的宇宙，结构和运动学去投影方程尚不清楚，在这里哈勃流（HF）拉伸了视线方向上的速度分布。 我们分析了由宇宙学模拟构建的93个模拟放松状态的星系团。 堆叠的模拟星系团可以用m=5的Einasto暗物质密度剖面很好地拟合，其速度各向异性（VA）接近Mamon-Lokas模型，且各向异性半径等于密度斜率-2。 闯入者的表面密度在到引力半径范围内几乎保持平坦，而它们的速度分布显示出主导的高斯星系团外围成分和平坦场成分。 这种在PPS中的闯入者分布在质量上几乎是普遍的。 局部kappa=2.7sigma速度截断返回了预期来自NFW密度和VA剖面的3D测量值的视线速度弥散剖面（LOSVDP）。 哈勃流导致更浅的外部LOSVDP，对于任何kappa值都无法很好地匹配Einasto模型。 在这个速度截断之后，移除六分之一的闯入者，闯入者仍然占VC内暗物质粒子的23%（接近观测到的偏离红序列的星系团星系比例）。 最佳拟合投影NFW或Einasto模型在速度截断后（前）低估了3D浓度的5%（15%），除非在拟合中包括恒定背景。 假设正确的质量剖面，通过测量的LOSVDP可以很好地恢复VA剖面，在外部区域有轻微的偏向更径向轨道的偏差。 附录提供了Einasto模型表面密度、投影质量和切向剪切剖面的解析近似。 显示英文摘要

摘要： When clusters of galaxies are viewed in projection, one cannot avoid picking up foreground/background interlopers, that lie within the virial cone (VC), but outside the virial sphere. Structural and kinematic deprojection equations are not known for an expanding Universe, where the Hubble flow (HF) stretches the line-of-sight distribution of velocities. We analyze 93 mock relaxed clusters, built from a cosmological simulation. The stacked mock cluster is well fit by an m=5 Einasto DM density profile, with velocity anisotropy (VA) close to the Mamon-Lokas model with anisotropy radius equal to that of density slope -2. The surface density of interlopers is nearly flat out to the virial radius, while their velocity distribution shows a dominant gaussian cluster-outskirts component and a flat field component. This distribution of interlopers in PPS is nearly universal in mass. A local kappa=2.7 sigma velocity cut returns the line-of-sight velocity dispersion profile (LOSVDP) expected from the NFW density and VA profiles measured in 3D. The HF causes a shallower outer LOSVDP that cannot be well matched by the Einasto model for any value of kappa. After this velocity cut, which removes 1 interloper out of 6, interlopers still account for 23% of DM particles within the VC (close to the observed fraction of cluster galaxies lying off the Red Sequence). The best-fit projected NFW or Einasto model underestimates the 3D concentration by 5% (15%) after (before) the velocity cut, unless a constant background is included in the fit. Assuming the correct mass profile, the VA profile is well recovered from the measured LOSVDP, with a slight bias towards more radial orbits in the outer regions. An appendix provides an analytical approximation to the surface density, projected mass and tangential shear profiles of the Einasto model.