天文观测对宇宙学的限制

发布时间：2018-02-28 13:41

本文关键词： 宇宙模型观测限制状态方程距离对偶关系不透明度　出处：《湖南师范大学》2012年博士论文　论文类型：学位论文

【摘要】：在过去的10-20年间,宇宙学从一门对观测数据非常渴望的学科逐渐成为了一门依靠观测数据来推动其发展的学科。对许多关键的参数(例如,物质密度分数Ωm,0,宇宙膨胀的减速因子q0)的测量精度可以控制在10%以内。在1998年之前,人们一直认为宇宙膨胀的速度是减小的,令人感到非常惊奇的是,Ia型超新星的观测结果却表明现今的宇宙正经历着一个加速膨胀的过程。基于这样的观测事实,人们推断宇宙中存在一种能产生负压强的物质能量组分,即暗能量,并得出其占到宇宙总物质能量的2/3左右。理解和认识暗能量的性质是现代物理学所面临的最大挑战之一。为了避开理解暗能量的奇异特性所带来的挑战,人们认为现有的爱因斯坦引力理论在宇宙的尺度上可能不再成立,而是需要对其进行适当的修正,这些理论可以在不引入暗能量的情况下解释宇宙的加速膨胀。迄今为止,大量的宇宙学模型被建立。同时,不同的天文观测所得到的数据样本越来越大,精度越来越高。这些数据将为我们揭开暗能量的神秘面纱,或者理解大尺度时的引力规律提供有力依据。因此,将理论模型和实验观测结果联系起来是非常必要的。本文前一部分讨论了最新的观测数据对一些主流的宇宙学模型的限制。我们发现,真空暗能量模型(ACDM)还是最被观测(SNLS3la型超新星,宙微波背景辐射和重子声学振荡的数据,以及哈勃参数的数据)所支持的候选者。然而,当只考虑SNLS3la型超新星数据时,DGP(膜世界理论)最被实验观测所支持。其次,借助于暗能量状态方程参数化的理论,我们利用观测数据讨论了宇宙膨胀加速度的演化,发现宇宙加速度有可能在过去的某时刻开始减小,甚至我们今天的宇宙已经进入了减速膨胀的阶段。但这些结果一定程度上依赖于状态方程的参数化形式和观测数据的选择。最后,我们用来自于超新星和星系团的观测数据,对宇宙学中联系两种重要距离的关系距离对偶关系,进行了不依赖宇宙学模型的检测,发现这个关系在实际观测中存在一定程度的偏离,且星系团样本的选择和X-射线的Chandra校准方法对检测结果有一定的影响。除此之外,我们利用距离对偶关系讨论了宇宙不透明度,发现现今观测还是支持一个完全透明的宇宙,并且支持宇宙学常数A0的情况。
[Abstract]:In the past 10-20 years, from a cosmological observation data are very eager to discipline has gradually become a rely on data to promote the development of the subject. For many of the key parameters (e.g., density fraction Omega m, 0, the expansion of the universe reduction factor Q0) the measurement accuracy can be controlled within 10%. Before 1998, people always think that the rate of expansion of the universe is reduced, amazing is that observations of type Ia supernovae but the results indicate that the present universe is experiencing an accelerated expansion process. This observation is based on the fact that people in the universe, there is a strong negative pressure can produce the material energy group the points, namely dark energy, and the total energy of the universe matter accounted for about 2/3. Understanding the nature of dark energy is one of the biggest challenges facing modern physics. In order to avoid the singular understanding of dark energy The challenges brought by the characteristics suggest that the existing Einstein's gravitational theory may no longer be established at the scale of the universe, but that it needs to be properly corrected. These theories can explain the accelerating expansion of the universe without introducing dark energy.
So far, a large number of cosmological model is established. At the same time, the sample data obtained by different astronomical observations more and more big, the accuracy is higher and higher. These data will help us to uncover the mystery of dark energy, or provide a strong basis for understanding the large-scale the law of gravity. Because of this, it is very necessary to observations the theoretical model and experiments together. The first part of this paper discusses the cosmological model of some of the mainstream of the latest observation data limitations. We found that the vacuum energy model (ACDM) is the most observed (type SNLS3la supernova, the cosmic microwave background radiation and baryon acoustic oscillation data, and Harbert data) the support of the candidates. However, when considering only the type SNLS3la supernova data, DGP (membrane theory world) is the most supported by experimental observations.
Secondly, with the help of the dark energy equation of state parameter theory, we use the observational data is discussed. The evolution of cosmic acceleration, acceleration may find the universe at some point in the past began to decrease, even today the universe has entered the decelerating stage. But these results must depend on the equation of state parameter the form and data selection.
Finally, we used data from supernovae and galaxy clusters, the relationship between distance duality between the cosmology of two important contact distance, detect does not depend on the cosmological model, found the relationship between a certain degree of deviation in the actual observations, and cluster sample selection and calibration method of X- ray Chandra have a certain influence on the test results. In addition, we use the distance duality relation discussed universe opacity, finds that the present observation still support a completely transparent universe, and supports the cosmological constant A0 situation.

【学位授予单位】：湖南师范大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：P159

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