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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/5970


    Title: 萊曼α吸收雲的運動學SZ效應所引起之宇宙背景輻射非均向性;Secondary Anisotropies Of Cosmic Microwave Background From The Kinematic Sunyaev-Zel’dovich Effect Of The Lyα Absorption systems
    Authors: 賴瑋倩;Wei-Chien Lai
    Contributors: 天文研究所
    Keywords: 萊曼阿爾發吸收雲;宇宙背景輻射;非均向性;Kinematic Sunyaev-Zel'dovich effect;Lyman alpha absorption systems;Cosmic Microwave Background;Secondary Anisotropies
    Date: 2001-07-19
    Issue Date: 2009-09-22 10:11:14 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 宇宙背景輻射包含原始的非均向性及次級的非均向性。這些次級的非均向性產生於recombination epoch之後,蘊藏著宇宙大尺度結構形成及演化的訊息。當我們將宇宙背景輻射溫度上的擾動畫在角功率譜(angular power spectrum)上,可看到在小角度的部分,也就是l>3000時,次級非均向性的值大過原始非均向性。而隨著宇宙背景輻射(CMB)觀測技術的大幅進展,不久後我們應可量測到這些次級非均向性。 我們根據目前對萊曼阿爾發吸收雲的觀測資料估算由此吸收雲引起的運動學SZ效應在CMB次級非均向性上的貢獻。由於萊曼阿爾發吸收雲具有整體運動速度,其系統內的自由電子會散射CMB光子,產生運動學SZ(KSZ)效應,而此效應在角度約數角分範圍扮演著重要的角色。 值得強調的一點是,我們的模擬是根據萊曼阿爾發吸收雲的觀測結果所做的估算,涉及猜測的成分最少,這是與目前大部分藉由動力學模擬的研究較不同的地方。我們得到的結果可拿來與未來的觀測做比較,對宇宙論參數,宇宙背景的離子化,及萊曼阿爾發吸收雲的性質會提供有力的規範。 The cosmic microwave background (CMB) has primary and secondary anisotropies. Secondary anisotropies are produced after the recombination epoch, which carry the information of structure formation and evolution history. When we expressed the CMB temperature fluctuations in angular power spectrum, secondary anisotropies dominate over the primary anisotropies at small angular scales ($ell$ $gtrsim$ 3000). With the developments of new instruments for CMB observations, the secondary anisotropies might be detectable in the near future. We estimate the contribution of the kinematic Sunyaev-Zeldovich (KSZ) effect of Lyman alpha absorption systems to the CMB. Since Lyman alpha absorbers possess bulk peculiar velocities, the free electrons in the systems would scatter the CMB photons and produce the KSZ effect. The effect can contribute significantly to the secondary anisotropies at angular size of arc minutes to sub arc minutes. It is important to emphasize that our simulations rely on the observations of Lyman alpha absorption systems with least speculation. The results here can put strong constraints on cosmological parameters, ionization history and the properties of Lyman alpha absorption systems by comparing with future observations.
    Appears in Collections:[Graduate Institute of Astronomy] Electronic Thesis & Dissertation

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