Compact groups in theory and practice – III. Compact groups of galaxies in the Sixth Data Release of the Sloan Digital Sky Survey
Compact groups in theory and practice – III. Compact groups of galaxies in the Sixth Data Release of the Sloan Digital Sky Survey
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DOI：
10.1111/j.1365-2966.2008.14340.x
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发表时间：
2008-12
影响因子：
4.8
通讯作者：
A. McConnachie;D. Patton;S. Ellison;L. Simard
中科院分区：
文献类型：
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作者：
A. McConnachie;D. Patton;S. Ellison;L. Simard
我们提出了最大的公开可用的目录的紧凑组（CG）的星系使用希克森的原始选择标准，从斯隆数字巡天（SDSS DR 6）的第六次数据发布选择。我们确定了2297个CG，其极限幅度为r = 18（0.24组度-2），74791个CG，其极限幅度为r = 21（0.67组度-2）。这代表了SDSS DR 6中所有星系在这些级别上的0.9%。由于光度计的总误差造成的污染已经从明亮的样本组中消除，我们估计它在大样本中的含量为14%。光谱信息可用于4131星系的明亮的目录（43%的完整性），我们发现，这些群体的中值红移是z MED = 0.09。亮星表中CG的中位视线速度色散为σ LOS = 230 km s-1，典型的星系间距为50-100 kpc。我们发现，与闯入的星系确定为成员的组的分数是在很好的协议，从我们以前的研究模拟星系目录的预测，我们演示了如何选择CG，这样的闯入者分数是很好的定义和最小化。这个观测数据集是理想的大型统计研究的CG，环境对星系演化的作用和影响的星系相互作用，在确定星系形态。
We present the largest publicly available catalogue of compact groups (CGs) of galaxies identified using the original selection criteria of Hickson, selected from the Sixth Data Release of the Sloan Digital Sky Survey (SDSS DR6). We identify 2297 CGs down to a limiting magnitude of r = 18 (∼0.24 groups deg -2 ), and 74 791 CGs down to a limiting magnitude of r = 21 (∼6.7 groups deg -2 ). This represents 0.9 per cent of all galaxies in the SDSS DR6 at these magnitude levels. Contamination due to gross photometric errors has been removed from the bright sample of groups, and we estimate it is present in the large sample at the 14 per cent level. Spectroscopic information is available for 4131 galaxies in the bright catalogue (43 per cent completeness), and we find that the median redshift of these groups is z med = 0.09. The median line-of-sight (LOS) velocity dispersion within the CGs from the bright catalogue is σ LOS ≃ 230 km s -1 , and their typical intergalactic separations are of the order of 50-100 kpc. We show that the fraction of groups with interloping galaxies identified as members is in good agreement with the predictions from our previous study of a mock galaxy catalogue, and we demonstrate how to select CGs such that the interloper fraction is well defined and minimized. This observational data set is ideal for large statistical studies of CGs, the role of environment on galaxy evolution and the effect of galaxy interactions in determining galaxy morphology.