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arXiv 0807.2216astro-ph
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在AMIGA计划范围内孤立星系的一个明确定义的样品的光度学特征

Photometric characterization of a well defined sample of isolated galaxies in the context of the AMIGA project

A. Durbala, J. W. Sulentic, R. Buta, L. Verdes-Montenegro

摘要:

我们进行了详细的光度分析(膨胀盘酒吧分解和浓度不对称丛生CAS参数化)的孤立星系,从孤立星系的目录(Karachentseva 1973年)提取和重新评估形态的AMIGA项目的背景下定义良好的样本。我们专注于Sb-Sc形态类型,因为它们是孤立的旋涡星系中最具代表性的人口。假设隆起Sersic指数和/或隆起/总光度比是合理的诊断伪与经典的凸起,我们得出结论,大多数晚型孤立盘星系可能主机pseudoclugges,而不是经典的凸起。我们的银河系隆起和磁盘的参数化表明,伪隆起的属性是强烈连接到磁盘。这可能表明,伪凸起是通过内部过程中形成的磁盘(即长期演变),酒吧可能在其形成中发挥重要作用。虽然所研究的样品涵盖了一个狭窄的形态范围内,Sb和Sbc-Sc类型之间的一个明确的分离,观察到在各种措施,例如前者是红色,明亮,有更大的磁盘和更大的酒吧,更明亮的凸起,更集中,更对称,比后者更丛生。与样本的螺旋星系(在相同的形态范围内)选择没有隔离标准的比较表明,孤立的星系往往主机更大的酒吧,更对称,不太集中,少clueries。

英文摘要:

We perform a detailed photometric analysis (bulge-disk-bar decomposition and Concentration-Asymmetry-Clumpiness - CAS parametrization) for a well defined sample of isolated galaxies, extracted from the Catalog of Isolated Galaxies (Karachentseva 1973) and reevaluated morphologically in the context of the AMIGA project. We focus on Sb-Sc morphological types, as they are the most representative population among the isolated spiral galaxies. Assuming that the bulge Sersic index and/or Bulge/Total luminosity ratios are reasonable diagnostics for pseudo- versus classical bulges, we conclude that the majority of late-type isolated disk galaxies likely host pseudobulges rather than classical bulges. Our parametrization of galactic bulges and disks suggests that the properties of the pseudobulges are strongly connected to those of the disks. This may indicate that pseudobulges are formed through internal processes within the disks (i.e. secular evolution) and that bars may play an important role in their formation. Although the sample under investigation covers a narrow morphological range, a clear separation between Sb and Sbc-Sc types is observed in various measures, e.g. the former are redder, brighter, have larger disks and larger bars, more luminous bulges, are more concentrated, more symmetric and clumpier than the latter. A comparison with samples of spiral galaxies (within the same morphological range) selected without isolation criteria reveals that the isolated galaxies tend to host larger bars, are more symmetric, less concentrated and less clumpy.

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