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arXiv 1008.4583astro-ph.CO
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一个环境依赖的Halo模型的理论研究

A Halo Model with Environment Dependence: Theoretical Considerations

Héctor Gil-Marín, Raul Jimenez, Licia Verde

摘要:

我们提出了一个修改的标准晕模型的目标是提供一个改进的描述星系聚类。最近的调查,如斯隆数字巡天(SDSS)和英澳两度巡天(2dF),显示星系的聚集与它们的属性(如金属丰度和恒星形成率)之间似乎存在相关性,这些属性被认为是环境依赖的。这种环境依赖性不包括在标准的晕模型中,其中宿主晕质量是指定星系属性的唯一变量。在我们的方法中,晕圈属性,即,浓度和晕圈占据分布(HOD)规定将不仅取决于晕圈质量(如在标准晕圈模型中),而且取决于晕圈环境。我们研究了不同的环境依赖性的晕浓度和HOD处方如何影响的关联函数。我们看到,在暗物质的水平上,晕的浓度只在小尺度上适度地影响暗物质的关联函数。然而,星系的关联函数是非常敏感的HOD的细节,即使只有一小部分晕的HOD被修改。

英文摘要:

We present a modification of the standard halo model with the goal of providing an improved description of galaxy clustering. Recent surveys, like the Sloan Digital Sky Survey (SDSS) and the Anglo-Australian Two-degree survey (2dF), have shown that there seems to be a correlation between the clustering of galaxies and their properties such as metallicity and star formation rate, which are believed to be environment-dependent. This environmental dependence is not included in the standard halo model where the host halo mass is the only variable specifying galaxy properties. In our approach, the halo properties i.e., the concentration, and the Halo Occupation Distribution --HOD-- prescription, will not only depend on the halo mass (like in the standard halo model) but also on the halo environment. We examine how different environmental dependence of halo concentration and HOD prescription affect the correlation function. We see that at the level of dark matter, the concentration of haloes affects moderately the dark matter correlation function only at small scales. However the galaxy correlation function is extremely sensitive to the HOD details, even when only the HOD of a small fraction of haloes is modified.

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