Bimodal Color Distribution in Hierarchical Galaxy Formation
Bimodal Color Distribution in Hierarchical Galaxy Formation
复制标题
分层星系形成中的双峰颜色分布
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
S. Salimbeni
中科院分区：
文献类型：
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作者：
N. Menci;A. Fontana;E. Giallongo;S. Salimbeni
我们展示了如何在星系图的框架下，根据合并历史的性质和本地星系前驱的反馈/恒星形成过程之间的相互作用，来解释观测到的星系颜色分布的双峰性。利用星系形成的半解析模型，计算了不同亮度星系的颜色分布，并与观测结果进行了比较。我们的基准点模型符合观测分布的基本性质，即：(1)比MR≲-18亮的天体呈明显的双峰分布，部分红色天体随着光度的增加而增加；(2)对于比MR≲-21亮的天体，颜色分布主要由u-r≈为2.2-2.4的红色天体主导；(3)红色星系群的分布分布比蓝色星系小；(4)在密度较高的环境中，即使是低亮度天体，红色星系的比例也较大；(5)分布的双峰性一直持续到z≈1.5.我们讨论了模型中包含的不同物理过程在产生上述结果中的作用。
We show how the observed bimodality in the color distribution of galaxies can be explained in the framework of the hierarchical clustering picture in terms of the interplay between the properties of the merging histories and the feedback/star formation processes in the progenitors of local galaxies. Using a semianalytic model of hierarchical galaxy formation, we compute the color distributions of galaxies with different luminosities and compare them with the observations. Our fiducial model matches the fundamental properties of the observed distributions, namely: (1) the distribution of objects brighter than Mr ≲ -18 is clearly bimodal, with a fraction of red objects increasing with luminosity; (2) for objects brighter than Mr ≲ -21, the color distribution is dominated by red objects with color u - r ≈ 2.2-2.4; (3) the spread on the distribution of the red population is smaller than that of the blue population; (4) the fraction of red galaxies is larger in denser environments, even for low-luminosity objects; and (5) the bimodality in the distribution persists up to z ≈ 1.5. We discuss the role of the different physical processes included in the model in producing the above results.