Photometric properties and scaling relations of early‐type Brightest Cluster Galaxies
Photometric properties and scaling relations of early‐type Brightest Cluster Galaxies
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DOI：
10.1111/j.1365-2966.2007.12818.x
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发表时间：
2007-12
影响因子：
4.8
通讯作者：
F. S. Liu;F. S. Liu;X. Xia;Shude Mao;Shude Mao;Hong Wu;Z. Deng
中科院分区：
文献类型：
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作者：
F. S. Liu;F. S. Liu;X. Xia;Shude Mao;Shude Mao;Hong Wu;Z. Deng
我们从C4星团目录中精心挑选了85个红移小于0.1的早期型最亮星团星系（BCGs）样本，研究了它们的光度特性。我们在斯隆r波段对这些BCGs进行了精确的背景减去和表面光度测定，达到25等弧秒2。通过定量分析BCGs的Petrosian剖面梯度，我们发现大部分BCGs在其外围有延伸的恒星包层；更明亮的BCGs往往有更大的恒星晕，这可能与合并有关。选取具有相似视星等和红移范围的椭圆星系作为比较样本，采用相同的光度分析方法。我们发现，与大多数早期型星系相比，BCGs具有更陡峭的尺寸-光度（R oc L”）和Faber-Jackson （L oc σ β）关系。此外，这些关系中的幂律指数（a和β）随着等高极限的加深而增加。对于22到25等角秒-2的等高限制，bcg通常比大部分早期型星系大，并且大部分（~ 49%）的bcg具有圆盘等高形状。尺度关系的差异与BCGs的动力学结构和形成路径可能不同于大部分早期型星系的情况一致；特别是干（无耗散）合并可能在它们的形成中起更重要的作用。在我们的示例中，我们突出了几个可能的干合并候选。
We investigate the photometric properties of the early-type Brightest Cluster Galaxies (BCGs) using a carefully selected sample of 85 BCGs from the C4 cluster catalogue with a redshift of less than 0.1. We perform accurate background subtractions and surface photometry for these BCGs to 25 mag arcsec -2 in the Sloan r band. By quantitatively analysing the gradient of the Petrosian profiles of BCGs, we find that a large fraction of BCGs have extended stellar envelopes in their outskirts; more luminous BCGs tend to have more extended stellar haloes that are likely to be connected with mergers. A comparison sample of elliptical galaxies was chosen with similar apparent magnitude and redshift ranges, for which the same photometric analysis procedure is applied. We find that BCGs have steeper size-luminosity (R oc L") and Faber-Jackson (L oc σ β ) relations than the bulk of early-type galaxies. Furthermore, the power-law indices (a and β) in these relations increase as the isophotal limits become deeper. For isophotal limits from 22 to 25 mag arcsec -2 , BCGs are usually larger than the bulk of early-type galaxies, and a large fraction (∼49 per cent) of BCGs have discy isophotal shapes. The differences in the scaling relations are consistent with a scenario where the dynamical structure and formation route of BCGs may be different from the bulk of early-type galaxies; in particular dry (dissipationless) mergers may play a more important role in their formation. We highlight several possible dry merger candidates in our sample.