The ATLAS3D project - XVII. Linking photometric and kinematic signatures of stellar discs in early-type galaxies-猫眼课题宝

DOI：

10.1093/mnras/sts315

发表时间：

2012-10

期刊：

Monthly Notices of the Royal Astronomical Society

影响因子：

4.8

通讯作者：

中科院分区：

物理与天体物理2区

文献类型：

作者：

D. Krajnović;K. Alatalo;L. Blitz;M. Bois;F. Bournaud;M. Bureau;M. Cappellari;R. Davies;T. Davis;P. Zeeuw;P. Duc;E. Emsellem;S. Khochfar;H. Kuntschner;R. McDermid;R. Morganti;T. Naab;T. Oosterloo;M. Sarzi;N. Scott;P. Serra;A. Weijmans;L. Young

我们分析了ATLAS（3D）样本中星系的形态结构，通过拟合一个单一的Sersic配置文件，并将所有非禁止对象（260个对象中的180个）分解为两个分量，由指数和一般Sersic函数参数化。这项分析的目的是寻找附近的早期型星系的光分布中的光盘的签名，并将它们与运动学特性进行比较。不建议使用单分量拟合的Sersic指数来区分慢转星系和快转星系，甚至晚型星系和早型星系。假设n > 3的天体是慢旋天体（或椭圆天体），那么只有22%的概率将其正确分类为慢旋天体（或37%的概率）。我们表明，指数的子组件，以及光配置文件只配备了一个单一的组成部分，低Sersic指数，可以与运动学证据盘在早期类型的星系。快旋和慢旋的圆盘与总光之比的中位数分别为0.41和0.0。同样，中位Sersic指数的隆起（一般Sersic分量）是1.7和4.8的快速和慢速旋转，分别。总的来说，盘或盘状结构存在于83%的早期类型星系中，这些星系没有酒吧，并且它们显示了完整的盘与总光比。早期星系中的圆盘占分析（非棒）物体总质量的40%左右。圆盘和凸起的分解可以作为快速和慢速旋转体之间分离的粗略近似，但它不能替代，因为正确识别慢速旋转体的概率只有59%。我们发现的角动量和光盘总光比和Sersic指数的凸起之间的趋势，在这个意义上说，高角动量星系有大的光盘总光比和小的凸起指数，但没有角动量和全球Sersic指数之间。我们调查的分解结果的倾斜效果，并确认，强指数分布可以区分，即使在低倾角，但中等大小的光盘是难以量化的，单独使用光度在倾角低于类似50度。动能（即投射角动量）仍然是减轻倾斜效应影响的最佳方法。我们还发现了质量和环境密度的微弱趋势，其中盘主导星系的质量通常较小，并且在所有密度下都可以找到，包括ATLAS（3D）样本采样的致密区域。

We analyse the morphological structures in galaxies of the ATLAS(3D) sample by fitting a single Sersic profile and decomposing all non-barred objects (180 of 260 objects) in two components parametrized by an exponential and a general Sersic function. The aim of this analysis is to look for signatures of discs in light distributions of nearby early-type galaxies and compare them to kinematic properties. Using Sersic index from single-component fits for a distinction between slow and fast rotators, or even late- and early-type galaxies, is not recommended. Assuming that objects with n > 3 are slow rotators (or ellipticals), there is only a 22 per cent probability to correctly classify objects as slow rotators (or 37 per cent of previously classified as ellipticals). We show that exponential sub-components, as well as light profiles fitted with only a single component of a low Sersic index, can be linked with the kinematic evidence for discs in early-type galaxies. The median disc-to-total light ratio for fast and slow rotators is 0.41 and 0.0, respectively. Similarly, the median Sersic indices of the bulge (general Sersic component) are 1.7 and 4.8 for fast and slow rotators, respectively. Overall, discs or disc-like structures are present in 83 per cent of early-type galaxies which do not have bars, and they show a full range of disc-to-total light ratios. Discs in early-type galaxies contribute with about 40 per cent to the total mass of the analysed (non-barred) objects. The decomposition into discs and bulges can be used as a rough approximation for the separation between fast and slow rotators, but it is not a substitute, as there is only a 59 per cent probability to correctly recognize slow rotators. We find trends between the angular momentum and the disc-to-total light ratios and the Sersic index of the bulge, in the sense that high angular momentum galaxies have large disc-to-total light ratios and small bulge indices, but there is none between the angular momentum and the global Sersic index. We investigate the inclination effects on the decomposition results and confirm that strong exponential profiles can be distinguished even at low inclinations, but medium-size discs are difficult to quantify using photometry alone at inclinations lower than similar to 50 degrees. Kinematics (i.e. projected angular momentum) remains the best approach to mitigate the influence of the inclination effects. We also find weak trends with mass and environmental density, where disc-dominated galaxies are typically less massive and found at all densities, including the densest region sampled by the ATLAS(3D) sample.

The ATLAS3D project - XVII. Linking photometric and kinematic signatures of stellar discs in early-type galaxies

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