Secular evolution and structural properties of stellar bars in galaxies
Secular evolution and structural properties of stellar bars in galaxies
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DOI：
10.1111/j.1365-2966.2011.18945.x
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发表时间：
2010-03
影响因子：
4.8
通讯作者：
D. Gadotti
中科院分区：
文献类型：
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作者：
D. Gadotti
我目前的结果从近300棒星系在本地宇宙中的恒星酒吧通过参数多分量多波段图像拟合建模。利用Sersic函数描述了棒的表面亮度径向分布，并确定了棒的有效半径、椭圆率、盒度、长度和质量以及棒与总亮度和质量的比值等参数，这对于这种尺寸的样品是前所未有的。比较了经典星系球和伪星系球中棒的性质。对于固定的棒与总质量比，伪凸起的平均质量明显小于经典凸起，这表明，如果伪凸起是通过棒形成的，则需要进一步的过程来构建经典凸起。我发现了杆件椭圆度和箱形度之间的关系，并将杆件强度定义为这两个量的乘积。我还发现酒吧的强度和归一化酒吧的大小之间的相关性，酒吧和凸起的大小之间的相关性，以及归一化酒吧的大小和凸起的总比率。在后两种相关性中，具有不同椭圆度的柱遵循平行线。如果从不同的标准化尺寸和椭圆度开始，由于星系内部到外部的角动量交换，随着动力学年龄的增长，棒变得更长更强，这些相关性就会出现，这与以前的理论预测一致。因此，酒吧模式的速度应成为酒吧动力学年龄较低，并朝着星系更突出的凸起。
I present results from the modeling of stellar bars in nearly 300 barred galaxies in the local universe through parametric multi-component multi-band image fitting. The surface brightness radial profile of bars is described using a Sersic function, and param- eters such as bar effective radius, ellipticity, boxiness, length and mass, and bar-to-total luminosity and mass ratios, are determined, which is unprecedented for a sample of this size. The properties of bars in galaxies with classical bulges and pseudo-bulges are compared. For a fixed bar-to-total mass ratio, pseudo-bulges are on average signif- icantly less massive than classical bulges, indicating that, if pseudo-bulges are formed through bars, further processes are necessary to build a classical bulge. I find a corre- lation between bar ellipticity and boxiness, and define bar strength as the product of these two quantities. I also find correlations between bar strength and normalised bar size, between the sizes of bars and bulges, and between normalised bar size and bulge- to-total ratio. Bars with different ellipticities follow parallel lines in the latter two correlations. These correlations can arise if, starting off with different normalised sizes and ellipticities, bars grow longer and stronger with dynamical age, as a result of an- gular momentum exchange from the inner to the outer parts of galaxies, in agreement with previous theoretical predictions. As a consequence, bar pattern speeds should become lower with bar dynamical age, and towards galaxies with more prominent bulges.