Structural properties of pseudo-bulges, classical bulges and elliptical galaxies: a Sloan Digital Sky Survey perspective
Structural properties of pseudo-bulges, classical bulges and elliptical galaxies: a Sloan Digital Sky Survey perspective
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DOI：
10.1111/j.1365-2966.2008.14257.x
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发表时间：
2008-10
影响因子：
4.8
通讯作者：
D. Gadotti
中科院分区：
文献类型：
--
作者：
D. Gadotti
我们已经进行了2D凸起/酒吧/光盘分解使用g，r和i波段图像的代表性样本的近1000个星系从斯隆数字巡天。我们发现，Petrosian集中指数是一个更好的代理膨胀比总的全球Sersic指数。我们表明，伪凸起可以区分从经典的凸起作为异常值的Kormendy关系。本文给出了椭圆星系、经典星系球、伪星系球、盘状星系和棒状星系的结构参数和质量分布，发现在局域宇宙中，大质量星系的总质量中，椭圆星系占32%、盘状星系占36%、经典星系球占25%、伪星系球占3%、棒状星系占4%。伪凸起目前正在经历激烈的星星形成活动，并填充颜色星等图的蓝色云。大多数（虽然不是全部）经典的凸起是静止的，并填充图中的红色序列。经典的凸起遵循凸起Sersic指数和凸起与总比率之间的相关性，而伪凸起不遵循。此外，对于固定的凸起与总的比率，伪凸起比经典凸起更不集中。伪凸起遵循的质量-尺寸关系与棒相似，而与经典凸起不同。在基本平面内，伪凸起占据与圆盘相同的轨迹。虽然这些结果指出了经典和伪凸起的不同形成过程，但我们也发现它们的性质存在显着重叠，表明不同的过程可能同时发生。最后，经典的凸起和椭圆星系遵循偏移的质量大小关系，这表明高质量凸起可能不仅仅是被圆盘包围的高质量椭圆星系。
We have performed 2D bulge/bar/disc decompositions using g, r and i-band images of a representative sample of nearly 1000 galaxies from the Sloan Digital Sky Survey. We show that the Petrosian concentration index is a better proxy for bulge-to-total ratio than the global Sersic index. We show that pseudo-bulges can be distinguished from classical bulges as outliers in the Kormendy relation. We provide the structural parameters and distributions of stellar masses of ellipticals, classical bulges, pseudo- bulges, discs and bars, and find that 32 per cent of the total stellar mass in massive galaxies in the local universe is contained in ellipticals, 36 per cent in discs, 25 per cent in classical bulges, 3 per cent in pseudo-bulges and 4 per cent in bars. Pseudo-bulges are currently undergoing intense star formation activity and populate the blue cloud of the colour-magnitude diagram. Most (though not all) classical bulges are quiescent and populate the red sequence of the diagram. Classical bulges follow a correlation between bulge Sersic index and bulge-to-total ratio, while pseudo-bulges do not. In addition, for a fixed bulge-to-total ratio, pseudo-bulges are less concentrated than classical bulges. Pseudo-bulges follow a mass-size relation similar to that followed by bars, and different from that followed by classical bulges. In the fundamental plane, pseudo-bulges occupy the same locus as discs. While these results point out different formation processes for classical and pseudo-bulges, we also find a significant overlap in their properties, indicating that the different processes might happen concomitantly. Finally, classical bulges and ellipticals follow offset mass-size relations, suggesting that high-mass bulges might not be simply high-mass ellipticals surrounded by discs.