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宇宙微波背景辐射

宇宙微波背景辐射. 郭宗宽. 中国科学院研究生院 2011 年 7 月 12 日. 引言. 宇宙学基本假设和理论基础 宇宙学原理（无边，无中心） 爱因斯坦引力理论 观测实验的重要性 超新星，大尺度结构， 宇宙微波背景 目前的进展和存在的问题 宇宙加速膨胀（暴涨，暗能量） 宇宙大尺度结构形成（暗物质）. 内容. 宇宙微波背景（ CMB ）辐射的形成 CMB 的发现和探测实验 CMB 的数据分析 CMB 各向异性的物理起源 CMB 的宇宙学解释 展望. 1. CMB 的形成. re combination decoupling.

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宇宙微波背景辐射

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  1. 宇宙微波背景辐射 郭宗宽 中国科学院研究生院 2011年7月12日

  2. 引言 • 宇宙学基本假设和理论基础 宇宙学原理（无边，无中心） 爱因斯坦引力理论 • 观测实验的重要性 超新星，大尺度结构，宇宙微波背景 • 目前的进展和存在的问题 宇宙加速膨胀（暴涨，暗能量） 宇宙大尺度结构形成（暗物质）

  3. 内容 • 宇宙微波背景（CMB）辐射的形成 • CMB的发现和探测实验 • CMB的数据分析 • CMB各向异性的物理起源 • CMB的宇宙学解释 • 展望

  4. 1. CMB的形成 • recombination • decoupling

  5. 2. CMB的发现和探测实验 • CMB was predicted by G. Gamow et al. in 1948 T~5 K • the first discovery of CMB radiation in 1964-1965 the Nobel Prize in Physics 1978: A.A. Penzias and R.W. Wilson • interpreted by P.J.E. Peebles, D.T. Wilkinson, et al. in 1965

  6. Hot big bang • COBE (Cosmic Background Explorer), launched on 18 Nov. 1989, 4 years the Nobel Prize in Physics 2006: J.C. Mather and G.F. Smoot J.C. Mather G.F. Smoot isotropy

  7. the COBE satellite experiments: • the Far InfraRed Absolute Spectrophotometer (FIRAS) team • the Differential Microwave Radiometer (DMR) team • advantages of satellite experiments: • no atmospheric thermal emission • full-sky map

  8. WMAP (Wilkinson Microwave Anisotropy Probe), launched on 30 June 2001, 9 years 141°

  9. free-free emission: electron-ion scattering • synchrotron emission: the acceleration of cosmic ray electrons in magnetic fields • thermal emission from dust

  10. foreground mask • angular power spectrum of CMB

  11. Planck, launched on 14 May 2009

  12. Other experiments: • ground based experiments (QUaD, BICEP, ACT, ACTPol from 2013) • balloon borne experiments (BOOMRANG, MAXIMA)

  13. 3. CMB的数据分析 time-ordered data full sky map spectrum parameter estimates • time-ordered data • the temperature anisotropies can be expanded in spherical harmonics

  14. for Gaussian random fluctuations, the statistical properties of the • temperature field are determined by the angular power spectrum For a full sky, noiseless experiments, • cosmological parameter estimation • likelihood function for a full sky: the sky-cut, MCMC

  15. 4. CMB各向异性的物理起源 • primary CMB anisotropies (at recombination) • inflation model (Alan H. Guth in 1981) • primordial power spectrum of curvature perturbations • angular power spectrum of CMB anisotropies V (φ) inflation φ reheating

  16. secondary CMB anisotropies (after recombination) • reionization • thermal Sunyaev-Zel’dovich effect • lensing effect • integrated Sachs-Wolf effect

  17. features of spectrum • large angular scales integrated SZ effect (<10) Sachs-Wolf effect (10~100) • intermediate scales acoustic oscillations (100~1000) • small scales (>1000) Silk damping: the dissipation of small-scale perturbations caused by photons' random walking out of overdense regions. For full accuracy, the Boltzmann equation must be solved to follow the evolution of the photon distribution function.

  18. 5. CMB的宇宙学解释

  19. the content of our Universe precision cosmology The stronger the contraction, the higher these peaks should be.

  20. 6. 展望 • the shape of the primordial power spectrum of curvature perturbations • detection of the primordial power spectrum of tensor perturbations • non-adiabaticity • non-Gaussianity

  21. 谢谢！

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