An algorithm for the reconstruction of the projected gravitational potential of galaxy clusters from galaxy kinematics
An algorithm for the reconstruction of the projected gravitational potential of galaxy clusters from galaxy kinematics
复制标题
从星系运动学重建星系团投影引力势的算法
DOI：
10.11588/heidok.00020178
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
E. Sarli-Waizmann
中科院分区：
文献类型：
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作者：
E. Sarli-Waizmann
在这项工作中，我们开发了一种方法，将信息从星系运动到重建的二维，投影星系团的引力势。 我们首先通过deprojecting所观察到的星系团星系的视线速度分散与应用贝叶斯定理，Richardson-Lucy方法，需要假设的形状的集群。在球对称的假设下，通过反投影得到星系的有效压力，即星系团的密度加权径向速度色散，然后利用星系的有效压力与密度之间的多变关系的假设，将其与三维引力势联系起来。二维引力势最后可以通过沿视线沿着直接投影得到。我们测试的方法与一个数值模拟的三轴星系团和其中确定的星系，并进行重建三个不同的视线，最初假设球度。在星系团的几何椭圆度中扩展引力势产生了对球面重建的二阶修正。 通过将我们的结果与直接从模拟中得到的投影引力势进行比较，我们发现，对于球状星团，用我们的重建方法得到的投影引力势与直接从模拟中得到的引力势之间的偏差在距星团中心维里半径（）的范围内，而对于椭球星团，在距星团中心维里半径（）的范围内偏差较小（小于）。
In this work we develop a method to incorporate the information from galaxy kinematics into the reconstruction of the two-dimensional, projected gravitational potential of galaxy clusters. We start by deprojecting the observed line-of-sight velocity dispersions of cluster galaxies with an application of Bayes' theorem, the Richardson-Lucy method, requiring the assumption of a shape for the cluster. Assuming spherical symmetry, after the deprojection we obtain an effective galaxy pressure, i.e. the density-weighted radial velocity dispersions of the cluster galaxies, which is then related to the three-dimensional gravitational potential by using the tested assumption of a polytropic relation between the effective galaxy pressure and the density. The two-dimensional gravitational potential can finally be found by straightforward projection along the line of sight. We test the method with a numerically simulated triaxial galaxy cluster and the galaxies identified therein and perform the reconstruction for three different lines of sight, initially assuming sphericity. Expanding the gravitational potential in the cluster's geometrical ellipticities yields second-order corrections to the spherical reconstruction. By comparing our results with the projected gravitational potential directly obtained from the simulation, we show that the deviation between the projected potential obtained with our reconstruction method and the potential directly extracted from the simulation iswithin approximately the virial radius () from the cluster centre in the case of a spherical cluster and remains moderate (below) within the same radius in the case of an ellipsoidal cluster.