大尺度环境对星系的实空间和红移空间成团性的影响
文献类型：学位论文
| 作者 | 200528002209010 |
| 学位类别 | 硕士 |
| 答辩日期 | 2008-06-10 |
| 授予单位 | 中国科学院上海天文台 |
| 授予地点 | 上海天文台 |
| 导师 | 景益鹏 |
| 关键词 | 星系 宇宙学 暗物质晕 |
| 其他题名 | Environmental Effects on Real-Space and Redshift-Space Galaxy Clustering |
| 中文摘要 | Galaxy formation inside dark matter halos, as well as the halo formation itself, can be affected by large-scale environments. Evaluating the imprints of environmental effects on galaxy clustering is crucial for precise cosmological constraints with data from galaxy redshift surveys. We investigate such an environmental impact on both real-space and redshift-space galaxy clustering statistics using a semi-analytic model (SAM) derived from the Millennium Simulation. We compare clustering statistics from original SAM galaxy samples and shuffled ones with environmental influence on galaxy properties eliminated. Among the several luminosity-threshold samples examined, the one most affected by environmental effects has a $\sim$10\% decrease in the real-space two-point correlation function~(2PCF) after shuffling. By decomposing the 2PCF into five different components based on the source of pairs, we show that the change in the 2PCF can be explained by the richness (galaxy occupation number) and formation time dependence of halo clustering. The 2PCFs in redshift space are found to change in a similar manner after shuffling. If the environmental effects are neglected, halo occupation distribution modeling of the real-space and redshift-space clustering may have a less than 6.5\% systematic uncertainty in constraining $\sigma_{8}\Omega_{m}^{0.6}$ from the most affected SAM sample and have substantially smaller uncertainties from the other samples. We argue that the effect could be even smaller in reality. In addition, we present a method to decompose the 2PCF, which can be applied to measure the two-point auto-correlation functions of galaxy sub-samples in a volume-limited galaxy sample and their two-point cross-correlation functions in a single run utilizing only one random catalog. |
| 英文摘要 | 暗晕中的星系形成和演化，以及暗晕本身的形成，都不同程度的受到大尺度环境的影响。评价环境效应对星系成团性的影响对于当今精确宇宙学的限制十分重要。我们利用基于千禧宇宙学模拟的一个星系形成的半解析模型（SAM），对实空间和红移空间的星系成团性中的环境效应分别进行了研。通过将原始的半解析星系样本按照所在暗晕质量进行打散和重新分配，我们得到了一系列褪去环境影响的对照样本，并对原始样本和对照样本的各种成团性的统计量进行了比较。在我们选取的六个光度限的星系样本中，实空间的两点相关函数（2PCF）受到最大的环境影响约为10\%。在将实空间的2PCF按照星系对的性质分解成不同的五个组份以后，我们发现2PCF上的环境效应可以被暗晕成团性对暗晕子结构丰度和形成时间的依赖性解决。红移空间中的两点相关函数在打散后的变化趋势和实空间中相似。如果忽略环境对星系成团性的影响，利用暗晕占据分布（HOD）对实空间和红移空间的模型限制得到的$\sigma_{8}\Omega_{m}^{0.6}$将会有6.5\%左右的系统误差。另外，我们提供了一种新的分解2PCF的方法，它可以一次性同时测量体积限星系子样本的自相关函数和互相关函数，并且只需要一个随机样本。 |
| 语种 | 中文 |
| 公开日期 | 2011-07-01 |
| 页码 | 49 |
| 源URL | [http://119.78.226.72//handle/331011/14720]  |
| 专题 | 上海天文台_中国科学院上海天文台学位论文 |
| 推荐引用方式 GB/T 7714 | 200528002209010. 大尺度环境对星系的实空间和红移空间成团性的影响[D]. 上海天文台. 中国科学院上海天文台. 2008. |
入库方式： OAI收割
来源：上海天文台
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