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標題: | 暗物質暈內在對齊於 f (R) 重力模擬下之應用 Intrinsic alignments of dark matter halos in f (R) gravity simulations |
作者: | Yao-Tsung Chuang 莊曜聰 |
指導教授: | 林彥廷 林彥廷(ytl@asiaa.sinica.edu.tw ) |
關鍵字: | 內在對齊,修正重力,f(R) 重力, Intrinsic alignments,modified gravity,f(R) gravity, |
出版年 : | 2022 |
學位: | 碩士 |
摘要: | 在理論觀測宇宙學中以星系形狀內在對齊(IA) 之統計方法探討宇宙的幾何與動力學在近年變得相當熱門,本論文中,我展示了首個於f(R) 修正重力的模擬宇宙下,測量暗物質暈之重力-橢圓率互相關函數(GI),以及橢圓率-橢圓率自相關函數(II),並且比較兩者在Λ–冷暗物質模擬宇宙中之差異,我們發現於f(R) 重力下雖然IA 統計的相關函數具有與在Λ-冷暗物質宇宙下的相似性,但還是有顯著的可辨識性,因此我們認為IA 統計有助於辨別這兩個不同的宇宙模型。再者,我們利用共變數矩陣及卡方檢定等統計方法,量化此可辨識性,並發現僅用傳統重力-重力相關函數測量紅移空間下的暗物質暈與結合IA 統計後相比,可辨識性相差40 個百分點。此外,我們還觀察到f(R) 重力宇宙下暗物質暈的短長軸比值與暗物質暈長軸指向之相關性強於Λ–冷暗物質宇宙。我們的結果不僅證明IA 統計的有效性及實用性,亦能作為未來探究修正重力與一般廣義相對論差異之參考。 There is a growing interest in utilizing intrinsic alignment (IA) of galaxy shapes as ageometric and dynamical probe of cosmology. In this work, we perform the first measurementsof IA in a modified gravity model using the gravitational shear-intrinsic ellipticity correlation (GI) and intrinsic ellipticity-ellipticity correlation (II) functions of dark-matter halos from f(R) gravity simulations. By comparing them with the same statistics measured in ΛCDM simulations, we find that the IA statistics in different gravity models show distinguishable features, with a trend similar to the case of conventional galaxy clustering statistics. Thus, the GI and II correlations are found to be useful in distinguishing between the ΛCDM and f(R) gravity models. More quantitatively, IA statistics enhance detectability of the imprint of f(R) gravity on large scale structures by ∼ 40% when combined with the conventional halo clustering in redshift space. We also find that the correlation between the axis ratio and orientation of halos becomes stronger in f(R) gravity than that in ΛCDM. Our results demonstrate the usefulness of IA statistics as a probe of gravity beyond a consistency test of ΛCDM and general relativity. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/84761 |
DOI: | 10.6342/NTU202203067 |
全文授權: | 同意授權(限校園內公開) |
電子全文公開日期: | 2022-09-05 |
顯示於系所單位: | 物理學系 |
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