Constraining cluster masses from the stacked phase space distribution at large radii
Constraining cluster masses from the stacked phase space distribution at large radii
复制标题
DOI：
10.1093/mnras/stz2227
复制
发表时间：
2018-09
影响因子：
4.8
通讯作者：
A. Hamabata;M. Oguri;T. Nishimichi
中科院分区：
文献类型：
--
作者：
A. Hamabata;M. Oguri;T. Nishimichi
速度色散已被用作测量团簇质量的一种方法。为了补充这种传统的方法，我们探索的可能性，约束集群质量从堆叠的相空间分布的星系在较大的半径，在那里的下落速度预计有一个集群质量的敏感性。首先，我们构建了一个双组分模型的三维相空间分布的晕周围的集群从集群中心的N体模拟的基础上达到50 $\，h^{-1}$ Mpc。我们确认，三维相空间分布显示出一个明确的集群质量依赖的最大规模检查。然后，通过在哈勃流的影响下将三维相空间分布沿着视线投影，计算星系团和晕之间成对视线速度的概率分布函数。我们发现，这个投影相空间分布，这可以直接与观测相比，显示出复杂的质量依赖性，由于之间的相互作用的速度和哈勃流。利用这个模型，我们估计了在距离星系团中心横向距离大于2，h^{-1}$ Mpc时，由投影相空间分布得到的动力学质量测量的精度.我们估计，通过使用1.5 × 105个分光星系，如果我们充分考虑来自我们模型的不准确性的系统误差，我们可以以14.5%的精度约束平均星系团质量。通过提高模型的准确性，这一比例可降至5.7%。
Velocity dispersions have been employed as a method to measure masses of clusters. To complement this conventional method, we explore the possibility of constraining cluster masses from the stacked phase space distribution of galaxies at larger radii, where infall velocities are expected to have a sensitivity to cluster masses. First, we construct a two-component model of the three-dimensional phase space distribution of haloes surrounding clusters up to 50 $\, h^{-1}$ Mpc from cluster centres based on N-body simulations. We confirm that the three-dimensional phase space distribution shows a clear cluster mass dependence up to the largest scale examined. We then calculate the probability distribution function of pairwise line-of-sight velocities between clusters and haloes by projecting the three-dimensional phase space distribution along the line of sight with the effect of the Hubble flow. We find that this projected phase space distribution, which can directly be compared with observations, shows a complex mass dependence due to the interplay between infall velocities and the Hubble flow. Using this model, we estimate the accuracy of dynamical mass measurements from the projected phase space distribution at the transverse distance from cluster centres larger than $2\, h^{-1}$ Mpc. We estimate that, by using 1.5 × 105 spectroscopic galaxies, we can constrain the mean cluster masses with an accuracy of 14.5 per cent if we fully take account of the systematic error coming from the inaccuracy of our model. This can be improved down to 5.7 per cent by improving the accuracy of the model.