论文标题
低质量星系基团的运动动荡
Kinematic unrest of low mass galaxy groups
论文作者
论文摘要
为了更好地了解星系组的形成，我们研究了宇宙进化调查（COSMOS）中大量光谱确认的X射线星系组的运动学，并对高达$ z = 1 $的星系组成员进行了高度采样。我们将结果与{\ sc Horizon-agn}的宇宙流体动力学模拟的预测进行了比较。利用对具有$ M _ {\ Mathrm {\ Mathrm {200C}} \ SIM 10^{12.6} -10^{14.50} M_ \ odot $的晕halo质量组的动力学的相位分析，我们在低质量星系组中表明，最明亮的组星系（BGG）（$ M _ {200c} <2c {200c} 10^{13} m_ \ odot $）相对于组速度分散，比高质量组具有更大的适当运动。 BGG适当速度与该组的速度分散的比率，$σ_{\ Mathrm {\ MathRM {bgg}}/σ_{Group} $，平均为$ 1.48 \ pm 0.13 $ 0.13 $，低质量组和$ 1.01 \ pm 0.09 \ pm 0.09 $ for高质量组。对{\ sc Horizon-agn}模拟的比较分析表明，尽管BGG质量的一致性在BGG特异性速度的幅度，形状和模式的一致性下仅在高质量组中实现了，但BGGS的特殊速度的传播量也有类似的增加。托管具有较大特殊速度的BGG的组更有可能被$ l_x-σ_{v} $关系所抵消；这可能是因为BGG的特殊运动受到新成员的积累的影响。
In an effort to better understand the formation of galaxy groups, we examine the kinematics of a large sample of spectroscopically confirmed X-ray galaxy groups in the Cosmic Evolution Survey (COSMOS) with a high sampling of galaxy group members up to $z=1$. We compare our results with predictions from the cosmological hydrodynamical simulation of {\sc Horizon-AGN}. Using a phase-space analysis of dynamics of groups with halo masses of $M_{\mathrm{200c}}\sim 10^{12.6}-10^{14.50}M_\odot$, we show that the brightest group galaxies (BGG) in low mass galaxy groups ($M_{\mathrm{200c}}<2 \times 10^{13} M_\odot$) have larger proper motions relative to the group velocity dispersion than high mass groups. The dispersion in the ratio of the BGG proper velocity to the velocity dispersion of the group, $σ_{\mathrm{BGG}}/σ_{group}$, is on average $1.48 \pm 0.13$ for low mass groups and $1.01 \pm 0.09$ for high mass groups. A comparative analysis of the {\sc Horizon-AGN} simulation reveals a similar increase in the spread of peculiar velocities of BGGs with decreasing group mass, though consistency in the amplitude, shape, and mode of the BGG peculiar velocity distribution is only achieved for high mass groups. The groups hosting a BGG with a large peculiar velocity are more likely to be offset from the $L_x-σ_{v}$ relation; this is probably because the peculiar motion of the BGG is influenced by the accretion of new members.
