非热起源暗物质模型中微波背景涨落和大尺度结构的研究
发布时间：2018-10-16 20:20
【摘要】：在过去的10年里,特别是2003年以来WMAP卫星对宇宙微波背景辐射的精确测量、斯隆数字化巡天对大尺度结构的观测以及更大样本的超新星等观测数据,使宇宙学的研究进入了精确宇宙学时代。目前,带有暗能量、具有标度不变的绝热原初扰动功率谱的冷暗物质(Cold Dark Matter, CDM)宇宙学模型被视为标准冷暗物质宇宙学模型(ACDM模型)。暗物质、宇宙微波背景涨落和宇宙大尺度结构是当前宇宙学的研究热点,这对于理解宇宙的物质分布和演化具有重要的意义。不同的暗物质模型会产生不同的微波背景涨落,影响大尺度结构的形成和演化。尽管ACDM宇宙学模型成功地解释了大尺度结构形成和演化,但在小尺度方面却不能与天文/宇宙学观测符合。本论文的目的就是要建立与观测符合的基于暗物质的标准宇宙学模型。为此,我们对暗物质和宇宙物质演化、宇宙大尺度结构展开了研究。在第一章,简要介绍了宇宙学的有关背景,包括标准宇宙学模型、结构形成理论,并介绍了宇宙中暗物质的观测依据、性质等；同时介绍了暗晕模型和描述暗晕特性的方法。在第二章,我们详细地给出了膨胀宇宙中,在标量场扰动下各种物质(包括重子、冷暗物质、光子、无质量的中微子、有质量的中微子)密度扰动的线性演化方程。这是计算各种宇宙学模型中物质扰动演化的线性转移函数的基础,也是计算高精度的微波背景涨落的角功率谱的基础。在第二章最后,给出了微波背景涨落的角功率谱的具体计算的表达式。在第三章,我们首先对ACDM宇宙学模型做了详细的介绍。基于WIMP暗物质模型,介绍了这种热起源暗物质的剩余丰度的标准计算；接着介绍了ACDM宇宙学模型在解释大尺度结构形成和演化的成功,以及面临的“小尺度危机”,即暗晕的卫星星系问题和中心密度问题。为了解决ACDM宇宙学模型的“小尺度危机”,我们建立了非热起源的WIMP暗物质模型。这种WIMP暗物质是通过宇宙相变产生的宇宙弦衰变而成的,是非热产生的WIMP暗物质(non-thermal production of WIMP dark matter,简称为NTDM)。在第三章我们详细介绍了NTDM粒子的产生机制；并给出了NTDM粒子的剩余丰度的计算；由目前的天文观测对宇宙学参数的测量,对宇宙弦形成时对称破缺尺度作出了限制。我们基于上一章推导物质密度扰动的线性演化方程的方法,给出了NTDM粒子的物质扰动的演化方程；并通过修改CMBFAST程序,得到NTDM的线性转移函数、微波背景涨落的温度功率谱、线性物质功率谱等的数值解。结合SDSS星系功率谱,分析了NTDM模型在解释宇宙大尺度结构方面的合理性。利用Lyman-α forest数据,对NTDM模型给出了限制,排除了过轻的NTDM粒子。最后建立了带有暗能量、具有标度不变的绝热原初扰动功率谱,基于非热起源的暗物质的宇宙学模型,即ANTDM宇宙学模型。在第四章,我们利用高分辨率的数值技术完成了在ANTDM宇宙学模型中,物质非线性演化过程的数值模拟,给出了暗物质的空间分布,并对暗物质的统计特性做了分析。喑物质数值模拟的一个直接应用是研究暗晕的分布和暗晕的高度非线性的内部结构。为此,我们基于球密度反差方法建立了暗晕模型。当整个晕的样本建立后,利用束缚粒子计算了暗晕的密度轮廓、质量函数等,并分析了暗晕的功率谱演化、暗晕的数密度演化,以及暗晕的形状等。同时,我们也对ACDM宇宙学模型完成了相同的数值模拟。通过不同宇宙学模型的数值模拟结果的比较和分析,说明了我们所建立的ANTDM模型在解释宇宙大尺度结构形成和演化方面的合理性；并由于NTDM粒子的非热起源机制,缓解了ACDM模型所面临的“小尺度危机”。最后一章是对本论文工作的总结,总结了整个论文的主要成果和创新点。特别是指出了在该方向进一步开展研究的思路和方法。
[Abstract]:In the past 10 years, especially since 2003, the WMAP satellite has made accurate measurement of the cosmic microwave background radiation, the observation of the large-scale structure and the supernovae of the larger samples, and so on. The Cold Dark Matter (CDM) continuum model with dark energy, with a scale-invariant adiabatic atomic perturbation power spectrum, is now considered a standard cold dark matter continuum model (ACDM model). Dark matter, cosmic microwave background fluctuation and large-scale structure of the universe are the focus of the current research, which is of great significance for understanding the material distribution and evolution of the universe. Different dark matter models will produce different microwave background fluctuations, which affect the formation and evolution of large-scale structures. Although the ACDM model has successfully explained the formation and evolution of large scale structures, it is not in conformity with astronomical/ astronomical observations in small scale aspects. The purpose of this thesis is to establish a standard model of dark matter based on dark matter. For this reason, we have studied the evolution of dark matter and the material of the universe and the large-scale structure of the universe. In the first chapter, the paper briefly introduces the background of the dark matter, including the standard model and the structure formation theory, and introduces the observation basis and properties of dark matter in the universe, and introduces the dark halo model and the method of describing the dark halo. In the second chapter, we give a detailed description of the linear evolution equation of the density disturbance of various substances (including baryons, cold dark matter, photons, non-mass neutrinos, and mass neutrinos) under the perturbation of scalar field. This is the basis for the calculation of the linear transfer function of material disturbance evolution in various mathematical models, and also the basis of calculating the angular power spectrum of the high-precision microwave background fluctuation. In the second chapter, the expression of the angle power spectrum of microwave background fluctuation is given. In chapter three, we first give a detailed introduction to the model of ACDM. Based on the WIMP dark matter model, the standard calculation of the residual abundance of the dark matter in this heat origin is introduced; then the success of the formation and evolution of the large scale structure is explained by the ACDM model, and the problems facing the 鈥渟mall scale crisis鈥，
本文编号：2275533
[Abstract]:In the past 10 years, especially since 2003, the WMAP satellite has made accurate measurement of the cosmic microwave background radiation, the observation of the large-scale structure and the supernovae of the larger samples, and so on. The Cold Dark Matter (CDM) continuum model with dark energy, with a scale-invariant adiabatic atomic perturbation power spectrum, is now considered a standard cold dark matter continuum model (ACDM model). Dark matter, cosmic microwave background fluctuation and large-scale structure of the universe are the focus of the current research, which is of great significance for understanding the material distribution and evolution of the universe. Different dark matter models will produce different microwave background fluctuations, which affect the formation and evolution of large-scale structures. Although the ACDM model has successfully explained the formation and evolution of large scale structures, it is not in conformity with astronomical/ astronomical observations in small scale aspects. The purpose of this thesis is to establish a standard model of dark matter based on dark matter. For this reason, we have studied the evolution of dark matter and the material of the universe and the large-scale structure of the universe. In the first chapter, the paper briefly introduces the background of the dark matter, including the standard model and the structure formation theory, and introduces the observation basis and properties of dark matter in the universe, and introduces the dark halo model and the method of describing the dark halo. In the second chapter, we give a detailed description of the linear evolution equation of the density disturbance of various substances (including baryons, cold dark matter, photons, non-mass neutrinos, and mass neutrinos) under the perturbation of scalar field. This is the basis for the calculation of the linear transfer function of material disturbance evolution in various mathematical models, and also the basis of calculating the angular power spectrum of the high-precision microwave background fluctuation. In the second chapter, the expression of the angle power spectrum of microwave background fluctuation is given. In chapter three, we first give a detailed introduction to the model of ACDM. Based on the WIMP dark matter model, the standard calculation of the residual abundance of the dark matter in this heat origin is introduced; then the success of the formation and evolution of the large scale structure is explained by the ACDM model, and the problems facing the 鈥渟mall scale crisis鈥，
本文编号：2275533
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