The Pseudo-evolution of Galaxy-cluster Masses and Its Connection to Mass Density Profile
The Pseudo-evolution of Galaxy-cluster Masses and Its Connection to Mass Density Profile
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DOI：
10.3847/1538-4357/ab3855
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发表时间：
2019-05
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影响因子：
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通讯作者：
M. Shirasaki
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作者：
M. Shirasaki
暗物质晕的质量通常被定义为相对于参考密度的球形超密度（SO）质量，而 SO 质量的时间演化可能受到参考密度的红移演化以及晕周围的物理质量吸积的影响。在这项研究中，我们首次通过 N 体模拟的时间序列中参考密度的变化来直接测量星团大小晕的 SO 质量的伪演化量。我们发现，z = 0 和 1 之间维里 SO 质量的 52% ± 19% 差异可以通过 z = 0 时维里质量为 1014 h−1 M⊙ 的星团的赝演化来解释。赝演化的量被发现与星系团的年龄和密度环境相关。 SO质量中伪演化量较大的星团大小晕的堆叠质量密度分布显示出较高的浓度和较大的线性偏差参数，这是已知的由于星团尺度上的浓度而导致的次级晕偏差的反例。我们讨论了更集中的星系团如何比不太集中的星系团表现出更大的聚类幅度，并认为丰富的丝状结构的存在在确定星系团的线性晕偏差方面起着关键作用。
A mass of dark matter halo is commonly defined as the spherical overdensity (SO) mass with respect to a reference density, whereas the time evolution of an SO mass can be affected by the redshift evolution of the reference density as well as the physical mass accretion around halos. In this study, we directly measure the amount of pseudo evolution of the SO masses of cluster-sized halos by the changes in the reference density from a time series of N-body simulations for the first time. We find that the 52% ± 19% difference in the virial SO masses between z = 0 and 1 can be accounted for by the pseudo evolution of clusters with a virial mass of 1014 h−1 M⊙ at z = 0. The amount of pseudo evolution is found to be correlated with the age and density environment of a galaxy cluster. The stacked mass density profiles of cluster-sized halos with a greater amount of pseudo evolution in the SO mass shows the higher concentration and greater linear bias parameter that is a counterexample of the known secondary halo bias due to concentration on the scale of clusters. We discuss how more concentrated clusters can show larger clustering amplitudes than their less concentrated counterparts and argue that the presence of rich filamentary structures plays a critical role in determining the linear halo bias of galaxy clusters.