从投影相空间分析邻近星系团的质量分布和星系轨道
Mass profiles and galaxy orbits in nearby galaxy clusters from the analysis of the projected phase-space
摘要：
我们分析了41个附近（z<0.1）放松星系团的运动学数据的投影相空间密度使用唯象，完全各向异性模型的分布函数。我们应用马尔可夫链蒙特卡罗方法放置约束的总质量分布近似的普遍NFW配置文件和配置文件的各向异性的星系轨道。在维里质量M_v= 5 × 10 ^{14}M_sun时，平均质量浓度关系的归一化值为c=6.9_{-0.7}^{+0.6}。假设σ_8与一致性模型框架中的质量浓度关系的归一化之间一一对应，我们估计线性功率谱的归一化为σ_8 =0.91_{-0.08}^{+0.07}。我们的质量配置文件的参数的约束进行了比较，从其他方法的估计。我们发现星系轨道在星系团中心是各向同性的（径向与切向速度色散的平均比值σ_r/σ_θ =0.97+/-0.04），在维里球处是径向各向异性的（平均比值σ_r/σ_θ =1.75^{+0.23}_{-0.19}）。虽然中心各向异性的值似乎是普遍的，但维里半径处的各向异性在1<（sigma_r/sigma_theta）<2的范围内在簇之间不同。利用Bautz-Morgan形态学分类和冷核突出的信息，我们选择了两个子样本的星系团对应于较低和较先进的演化状态。研究表明，演化程度较低的星系团具有较浅的质量分布，它们的星系轨道在维里球上更偏向径向。这一属性是一致的质量分布的预期演变，以及与观测到的轨道分离的晚型和早型星系。
英文摘要：
We analyze kinematic data of 41 nearby (z<0.1) relaxed galaxy clusters in terms of the projected phase-space density using a phenomenological, fully anisotropic model of the distribution function. We apply the Markov Chain Monte Carlo approach to place constraints on total mass distribution approximated by the universal NFW profile and the profile of the anisotropy of galaxy orbits. We find the normalization of the mean mass-concentration relation is c=6.9_{-0.7}^{+0.6} at the virial mass M_v=5x10^{14}M_sun. Assuming a one-to-one correspondence between sigma_8 and the normalization of the mass-concentration relation in the framework of the concordance model we estimate the normalization of the linear power spectrum to be sigma_8=0.91_{-0.08}^{+0.07}. Our constraints on the parameters of the mass profile are compared with estimates from other methods. We show that galaxy orbits are isotropic at the cluster centres (with the mean ratio of the radial-to-tangential velocity dispersions sigma_r/sigma_theta=0.97+/-0.04) and radially anisotropic at the virial sphere (with the mean ratio sigma_r/sigma_theta=1.75^{+0.23}_{-0.19}). Although the value of the central anisotropy appears to be universal, the anisotropy at the virial radius differs between clusters within the range 1<(sigma_r/sigma_theta)<2. Utilizing the Bautz-Morgan morphological classification and information on the prominence of a cool core we select two subsamples of galaxy clusters corresponding to less and more advanced evolutionary states. It is demonstrated that less evolved clusters have shallower mass profiles and their galaxy orbits are more radially biased at the virial sphere. This property is consistent with the expected evolution of the mass profiles as well as with the observed orbital segregation of late and early type galaxies.
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