三点相关统计的理论与测量

发布时间：2018-01-29 23:29

本文关键词： 数值模拟相关函数依赖性扰动理论双谱光度暗物质星系模型构建密度场　出处：《天文学进展》2011年01期 　论文类型：期刊论文

【摘要】：本文分别从数值模拟、理论和观测的角度研究和分析了三点相关函数以及双谱对尺度、形状和光度等的依赖性,并比较了数值模拟与二阶扰动理论以及暗晕模型的差别。我们发现二阶扰动理论即使在线性尺度上也是与数值模拟存在明显偏差的,它并不足以很好地描述暗物质双谱在大尺度上的行为。如果要与数值模拟更好地吻合,我们需要引入更高阶的修正。我们用其他人的半解析模型构建了对应于我们数值模拟的模拟星系样本,并计算了不同光度星系样本的双谱从而得到了相应的星系偏袒值。我们发现,对星系密度场的泰勒二阶展开是可以适用到准线性尺度k(?)0.15h/Mpc上的,但是要通过三点相关来获得准确的星系偏袒值,我们需要拥有对暗物质密度场的准确估计,这却是二阶非线性扰动理论所无法做到的。暗晕模型在定性描述双谱行为方面是十分有效的,但是它与数值模拟的定量比较还是存在很多不同。要用暗晕模型来精确描述双谱,我们需要对模型的各种设定做出精细的调节和改进。最后,我们还利用了SDSS的最新观测数据测量了红移空间的三点相关函数以及投影三点相关函数,并研究它们对于星系光度、颜色和恒星质量等性质的依赖关系。我们发现,不同于之前的许多工作,星系的归约三点相关函数对光度存在明显的依赖性,而这种依赖性却是与三角形的形状和尺度耦合在一起。三点相关对恒星质量的依赖与光度依赖性十分类似。而颜色的依赖性在小尺度上则比光度和恒星质量更显著一些。
[Abstract]:In this paper, we study and analyze the dependence of three point correlation function and bispectrum on scale, shape and luminosity respectively from the point of view of numerical simulation, theory and observation. The difference between numerical simulation and second-order perturbation theory as well as dark halo model is compared. It is found that the second-order perturbation theory is obviously deviated from numerical simulation even on linear scale. It is not enough to describe the behavior of dark matter bispectrum on a large scale. We need to introduce higher-order corrections. We have constructed simulated galaxy samples corresponding to our numerical simulations using other people's semi-analytical models. We have calculated the bispectrum of different luminosity galactic samples and obtained the corresponding galactic bias. We find that the Taylor second-order expansion of the galactic density field can be applied to the quasi-linear scale KG? On 0.15 h / MPC, but to get the exact galaxy bias by three points of correlation, we need to have an accurate estimate of the dark matter density field. This is not possible by the second-order nonlinear perturbation theory, and the dark halo model is very effective in describing the bispectral behavior qualitatively. However, there are still many differences between it and numerical simulation. In order to accurately describe bispectrum by dark halo model, we need to fine-tune and improve the various settings of the model. Finally. We also measured the three point correlation function and the projection three point correlation function of the redshift space using the latest observations of SDSS and studied their luminosity for galaxies. We find that, unlike many previous work, the reduction three-point correlation function of galaxies is obviously dependent on luminosity. This dependence is coupled with the shape and scale of a triangle. The dependence of three-point correlation on star mass is very similar to that of photometric dependence, while color dependence is more apparent on a small scale than photometric or stellar mass. With some.
【作者单位】：中国科学院上海天文台星系宇宙学重点实验室;
【分类号】：P145.9
【正文快照】： 三点相关统计的理论与测量@郭宏$中国科学院上海天文台星系宇宙学重点实验室!上海 200030本文分别从数值模拟、理论和观测的角度研究和分析了三点相关函数以及双谱对尺度、形状和光度等的依赖性,并比较了数值模拟与二阶扰动理论以及暗晕模型的差别。我们发现二阶扰动理论即使

【相似文献】