Testing model predictions of the cold dark matter cosmology for the sizes, colours, morphologies and luminosities of galaxies with the SDSS
Testing model predictions of the cold dark matter cosmology for the sizes, colours, morphologies and luminosities of galaxies with the SDSS
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DOI：
10.1111/j.1365-2966.2009.15057.x
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发表时间：
2008-12
影响因子：
4.8
通讯作者：
J. González;C. Lacey;C. Baugh;C. Frenk;A. Cosmology;Durham;Caltech
中科院分区：
文献类型：
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作者：
J. González;C. Lacey;C. Baugh;C. Frenk;A. Cosmology;Durham;Caltech
斯隆数字巡天（SDSS）的巨大尺寸和均匀性使得对当前星系形成模型的严格测试成为可能。我们比较了galform半解析星系形成模型对本地星系的光度、形态、颜色和标度的预测。galform模型的光度和大小的盘和星系的隆起部分，所以我们可以计算的数量，可以直接与SDSS观测，如彼得罗斯等和Sersic指数。我们测试了两个已发表的冷暗物质宇宙学模型的预测：Baugh等人的模型，它假设了一个头重脚轻的初始质量函数（IMF）在恒星爆发和超风反馈，和Bower等人的模型，它使用活动星系核反馈和标准IMF。Bower等人的模型更好地再现了SDSS数据中观察到的光度函数、形态-光度关系和颜色双峰性的整体形状，但与尺寸-光度关系的匹配较差。Baugh等人的模型成功地预言了晚型星系的大小-光度关系。这两个模型都无法重现明亮的早期星系的大小。这些问题凸显了需要更好地理解反馈过程在确定星系大小中的作用，特别是超新星重新加热的气体角动量的处理，以及星系合并和盘不稳定形成的恒星球体的大小。
The huge size and uniformity of the Sloan Digital Sky Survey (SDSS) make possible an exacting test of current models of galaxy formation. We compare the predictions of the galform semi-analytical galaxy formation model for the luminosities, morphologies, colours and scalelengths of local galaxies. galform models the luminosity and size of the disc and bulge components of a galaxy, and so we can compute quantities which can be compared directly with SDSS observations, such as the Petrosian magnitude and the Sersic index. We test the predictions of two published models set in the cold dark matter cosmology: the Baugh et al. model, which assumes a top-heavy initial mass function (IMF) in starbursts and superwind feedback, and the Bower et al. model, which uses active galactic nucleus feedback and a standard IMF. The Bower et al. model better reproduces the overall shape of the luminosity function, the morphology–luminosity relation and the colour bimodality observed in the SDSS data, but gives a poor match to the size–luminosity relation. The Baugh et al. model successfully predicts the size–luminosity relation for late-type galaxies. Both models fail to reproduce the sizes of bright early-type galaxies. These problems highlight the need to understand better both the role of feedback processes in determining galaxy sizes, in particular the treatment of the angular momentum of gas reheated by supernovae, and the sizes of the stellar spheroids formed by galaxy mergers and disc instabilities.