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arXiv 0712.0927astro-ph
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早型布里渊团簇星系的光度特性和标度关系

Photometric Properties and Scaling Relations of Early Type Brightest Cluster Galaxies

F. S. Liu, X. Y. Xia, Shude Mao, Hong Wu, Z. G. Deng

摘要:

本文利用从C4星系团星表中精心挑选的85个红移小于0.1的早型布里渊星系团的光度学性质进行了研究。我们进行精确的背景扣除,并为这些BCGs表面光度测定到25 $\magsec$在斯隆$r$带。通过定量分析的BCGs的彼得罗相配置文件的梯度,我们发现,很大一部分的BCGs扩展恒星的信封在其郊区,更明亮的BCGs往往有更多的扩展恒星晕,可能与合并。选择了一个具有相似视星等和红移范围的椭圆星系作为比较样本,并采用了相同的光度分析程序。我们发现BCGs的尺寸-光度($R \propto L^α$)和Faber-Jackson($L \propto σ^β$)关系比早期类型星系的大部分都要陡。此外,这些关系中的幂律指数($α$和$β$)随着等照度线极限变深而增加。当等光度线的极限为22 ~ 25 $\magsec$时,BCGs通常比早期类型星系的大部分大,并且大部分($\sim 49%$)的BCGs具有盘状等光度线形状。的标度关系的差异是一致的情况下,BCGs的动力学结构和形成路线可能是不同的大部分早期类型的星系,特别是干(无耗散)合并可能会发挥更重要的作用,在他们的形成,我们突出几个可能的干合并候选人在我们的样本。

英文摘要:

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 redshift less than 0.1. We perform accurate background subtractions, and surface photometry for these BCGs to 25 $\magsec$ 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 halos that are likely 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 ($R \propto L^α$) and Faber-Jackson ($L \propto σ^β$) relations than the bulk of early type galaxies. Furthermore, the power-law indices ($α$ and $β$) in these relations increase as the isophotal limits become deeper. For isophotal limits from 22 to 25 $\magsec$, BCGs are usually larger than the bulk of early type galaxies, and a large fraction ($\sim 49%$) of BCGs have disky 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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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