以宇宙微波背景輻射觀測結果估計星系團性質與宇宙拓樸

Abstract

在這篇論文當中, 我們研究兩種重要的宇宙微波背景輻射次級效應: 桑-濟效應與宇宙拓樸。在論文的第一部份, 我們利用李遠哲陣列所觀測到六個星系團造成的桑-濟效應, 推測這些星系團的電子溫度、質量、以及康普敦散射係數等物理性質。我們同時考慮了兩種星系團模型: 熱平衡貝它模型與普遍溫度模式貝它模型。我們對於星系團物理性質的推估,與其它研究團隊使用桑-濟效應與X 射線觀測資料所得結果相吻合。我們的結果顯示出只靠桑-濟效應的微波關測結果估計星系團性質是可能的。在第二部份, 我們模擬在六種可能的平坦有限宇宙拓樸當中, 宇宙微波背景輻射溫度與極化性的功率譜。我們將模擬所得之功率譜與威爾金森微波非均向性探測衛星的實際觀測結果做比較。我們的結果顯示威爾金森微波非均向性探測衛星的觀測結果有利於有限大小的宇宙拓樸模型。我們估計宇宙的大小大約是最後散射面半徑的1.14倍。同時我們也對於普朗克衛星觀測結果所可能對於宇宙拓樸估計做出的貢獻進行預測。

In this thesis we studied two important cosmic microwave background (CMB) secondary effects: Sunyaev-Zel’dovich effect (SZE) and cosmological topology. In the first part, we estimated electron temperature, mass, and integrated Compton Y of six galaxy clusters using SZE observation data obtained with the Y. T. Lee Array for Microwave Background Anisotropy (AMiBA). We modified an iterative method, based on isothermal beta-models, to derive these cluster properties. The non-isothermal universal temperature profile (UTP) beta-model was also considered. Our results are in good agreement with previous results deduced from other X-ray and SZE observations. Our results suggest that cluster properties may be measurable with SZE observations alone. In the second part, we simulated CMB temperature and polarization power spectrum in universes with six compact and orientable non-trivial topologies with flat geometry. We also compared our simulated power spectrum with observation results from Wilkinson Microwave Anisotropy Probe (WMAP) to estimate the size of 3-torus topology. Our results suggest that the power spectrum observed by WMAP favors the finite universe model with the size 1.14 times of the radius of last scattering surface. We also conducted a forecast of the ability of upcoming PLANCK to constrain the topology of our Universe.