Diversity in the stellar velocity dispersion profiles of a large sample of brightest cluster galaxies z ≤ 0.3
Diversity in the stellar velocity dispersion profiles of a large sample of brightest cluster galaxies z ≤ 0.3
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DOI：
10.1093/mnras/sty498
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发表时间：
2018-02
影响因子：
4.8
通讯作者：
S. I. Loubser;H. Hoekstra;A. Babul;E. O’Sullivan
中科院分区：
文献类型：
--
作者：
S. I. Loubser;H. Hoekstra;A. Babul;E. O’Sullivan
为了研究星系团的速度色散分布，我们分析了位于32个质量星系团中的最亮星系团(BCG)的空间分辨深光学光谱，这些星系团的红移为0.05美元。我们将这些测量结果与其他大质量早期类型星系的测量结果进行了比较，并在相关情况下与中心群星系进行了比较。这个独特的大样本延伸到最极端的大质量星系，横跨-25.7到-27.8 MAG之间的M${K}$，以及主机星系团晕质量M$_{500}$高达1.7$\x$10$^{15}$M${\ODOT}$。为了比较最亮星系群和星系团成员之间的运动学性质，我们分析了来自完整局部体积星系群样本(CLOGS)的23个附近最亮星系群(BGGS)的类似空间分辨长缝光谱。我们发现BCG的速度色散斜率有惊人的变化，其中正斜率的比例要大得多，与其他(非中心)早期类型星系以及这些星系群中大多数最亮的成员相比，这是独一无二的。我们发现BCGS和BGGS的速度色散斜率与星系的光度相关，并对这种关系进行了量化。目前尚不清楚我们所看到的速度分散斜率的完全多样性是否在模拟中重现。
We analyse spatially-resolved deep optical spectroscopy of Brightest Cluster Galaxies (BCGs) located in 32 massive clusters with redshifts of 0.05 $\leq z \leq$ 0.30, to investigate their velocity dispersion profiles. We compare these measurements to those of other massive early-type galaxies, as well as central group galaxies, where relevant. This unique, large sample extends to the most extreme of massive galaxies, spanning M$_{K}$ between -25.7 to -27.8 mag, and host cluster halo mass M$_{500}$ up to 1.7 $\times$ 10$^{15}$ M$_{\odot}$. To compare the kinematic properties between brightest group and cluster members, we analyse similar spatially-resolved long-slit spectroscopy for 23 nearby Brightest Group Galaxies (BGGs) from the Complete Local-Volume Groups Sample (CLoGS). We find a surprisingly large variety in velocity dispersion slopes for BCGs, with a significantly larger fraction of positive slopes, unique compared to other (non-central) early-type galaxies as well as the majority of the brightest members of the groups. We find that the velocity dispersion slopes of the BCGs and BGGs correlate with the luminosity of the galaxies, and we quantify this correlation. It is not clear whether the full diversity in velocity dispersion slopes that we see is reproduced in simulations.