Evolution in the discs and bulges of group galaxies since z= 0.4
Evolution in the discs and bulges of group galaxies since z= 0.4
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自 z= 0.4 起星系团盘和核球的演化
DOI：
10.1111/j.1365-2966.2008.13340.x
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发表时间：
2008
影响因子：
4.8
通讯作者：
Ociw
中科院分区：
文献类型：
--
作者：
S. McGee;M. Balogh;Robert D E Henderson;D. Wilman;R. Bower;J. Mulchaey;Augustus Oemler Jr. Waterloo;Mpe;Garching;D. University;Ociw
我们利用哈勃太空望远镜(HST)高级相机(ACS)和GIM2D表面亮度拟合软件包，对0.3<；z<；0.55处光学选择的群星系样本进行了定量形态测量。这组样本来自加拿大观测宇宙学、场星系红移测量(CNOC2)和后续麦哲伦光谱学。我们将这些测量结果与千禧年银河系星表(MGC)中0.05<；z<；0.12的类似样本进行了比较。我们发现，在这两个时期，群和场的分数膨胀光度(B/T)分布明显不同，主要的差异是在群样本中缺乏以盘状为主的(B/T<；0.2)星系。在固定光度下，z=0.4群的盘状星系的∼比磁场少5.5%±2%，而当z=0.1时，这种差异增加到∼19%±6%。尽管存在形态进化，但我们没有看到任何证据表明，群体环境正在积极地干扰或以其他方式影响整个现有的椎间盘种群。在这两个红移中，群星系的盘具有类似的标度关系，并且表现出与场星系的盘相似的中值不对称性。我们确实发现了证据表明，高度不对称的、以膨胀为主的星系群的比例比野外高6%±3%，这表明在群环境中可能存在增强的合并。我们使用Bower等人的半解析星系星表在z=0.4和0复制了我们的组样本。该模型准确地再现了z=0.1时群和场的B/T分布。然而，该模型没有再现我们的发现，即自z=0.4以来，组中的光盘赤字显著增加。
We present quantitative morphology measurements of a sample of optically selected group galaxies at 0.3 < z < 0.55 using the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) and the GIM2D surface brightness fitting software package. The group sample is derived from the Canadian Network for Observational Cosmology Field Galaxy Redshift Survey (CNOC2) and follow-up Magellan spectroscopy. We compare these measurements to a similarly selected group sample from the Millennium Galaxy Catalogue (MGC) at 0.05 < z < 0.12. We find that, at both epochs, the group and field fractional bulge luminosity (B/T) distributions differ significantly, with the dominant difference being a deficit of disc-dominated (B/T < 0.2) galaxies in the group samples. At fixed luminosity, z = 0.4 groups have ∼5.5 ± 2 per cent fewer disc-dominated galaxies than the field, while by z = 0.1 this difference has increased to ∼19 ± 6 per cent. Despite the morphological evolution we see no evidence that the group environment is actively perturbing or otherwise affecting the entire existing disc population. At both redshifts, the discs of group galaxies have similar scaling relations and show similar median asymmetries as the discs of field galaxies. We do find evidence that the fraction of highly asymmetric, bulge-dominated galaxies is 6 ± 3 per cent higher in groups than in the field, suggesting there may be enhanced merging in group environments. We replicate our group samples at z = 0.4 and 0 using the semi-analytic galaxy catalogues of Bower et al. This model accurately reproduces the B/T distributions of the group and field at z = 0.1. However, the model does not reproduce our finding that the deficit of discs in groups has increased significantly since z = 0.4.