论文标题
hiflugcs星系簇中的质量分散关系
Mass-Velocity Dispersion Relation in HIFLUGCS Galaxy Clusters
论文作者
论文摘要
我们研究了最高X射线通量星系群集样品（HiflugCs）中29个星系簇中的质量分散关系（MVDR）。我们测量了这些簇的空间分辨，视线速度分散曲线，我们发现它们在大半径上大部分是平坦的，让人联想到星系的旋转曲线。我们发现了Baryonic Mass $ M_ \ MATHRM {BAR} $与成员星系的平坦速度分散$σ$之间的紧密经验关系，即mvdr， $ \ log（m_ \ mathrm {bar}/m _ \ odot）= 4.1^{+0.4} _ { - 0.4} \，\ log（σ/\ mathrm {km} \，\ Mathrm {km} \，\ mathrm {s} $ 12^{+3} _ { - 3} \％$的散布。 MVDR的残差与其他簇特性不相关，例如温度，簇半径，重型质量表面密度和红移。这些特征让人联想到单个星系的MVDR，尽管特征加速度范围更大的十倍。簇bary级分数不到宇宙价值，暴露出一个问题：对于较低的质量和较低的baryonic加速度簇，差异会系统地增加。
We investigate the mass-velocity dispersion relation (MVDR) in 29 galaxy clusters in the HIghest X-ray FLUx Galaxy Cluster Sample (HIFLUGCS). We measure the spatially resolved, line-of-sight velocity dispersion profiles of these clusters, which we find to be mostly flat at large radii, reminiscent of the rotation curves of galaxies. We discover a tight empirical relation between the baryonic mass $M_\mathrm{bar}$ and the flat velocity dispersion $σ$ of the member galaxies, i.e. MVDR, $\log(M_\mathrm{bar}/M_\odot)=4.1^{+0.4}_{-0.4}\,\log(σ/\mathrm{km}\,\mathrm{s}^{-1})+1.6^{+1.0}_{-1.3}$, with the lognormal intrinsic scatter of $12^{+3}_{-3}\%$. The residuals of the MVDR are uncorrelated with other cluster properties like temperature, cluster radius, baryonic mass surface density, and redshift. These characteristics are reminiscent of the MVDR for individual galaxies, albeit about ten times larger characteristic acceleration scale. The cluster baryon fraction falls short of the cosmic value, exposing a problem: the discrepancy increases systematically for clusters of lower mass and lower baryonic acceleration.
