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標題: | 再探模糊暗物質中的核心-暈關係 Revisit the Core-Halo Relation in Fuzzy Dark Matter |
作者: | 廖品瑜 Pin-Yu Liao |
指導教授: | 薛熙于 Hsi-Yu Schive |
關鍵字: | 模糊暗物質,數值模擬,暗物質暈,孤子核心,解析度, fuzzy dark matter,numerical simulation,dark matter halo,soliton core,resolution, |
出版年 : | 2023 |
學位: | 碩士 |
摘要: | 在模糊暗物質(Fuzzy Dark Matter, FDM)中,暗物質暈的中心會形成孤子核心。先前的研究根據薛丁格-泊松方程和不確定性原理的縮放對稱性,預測核心質量與暈質量之間存在一個特定比例關係。然而模擬結果顯示大質量暈的結果與此比例關係偏離,卻缺乏合理的解釋。在本研究中,我們首先提出這種不一致部分是由於模擬分辨率不足,無法解析模糊暗物質的量子壓力,導致暈和核心都出現非物理壓縮所致。通過適當的分辨率,我們模擬中的FDM暈可以與冷暗物質(Cold Dark Matter, CDM)對應非常吻合,並且核心質量更接近預期值。在我們的後續分析中,我們通過將傳統的頂帽模型(Top-Hat Model)改善為廣泛接受的NFW(Navarro-Frenk-White)剖面,提高了位能之準確性。此外,我們逐步分析了暈內部結構的溫度,發現在大質量之暈中,理論核心-暈關係中假設的等溫性並不滿足,導致核心質量被低估。我們還觀察到核心與周遭的溫度並不完全相同,而是存在一個常數差異,這種差異可能是由於孤子本身的特性所引起的。這些新發現修正了核心-暈關係並進一步讓我們對早期宇宙中凝聚核心如何形成有更深刻的理解。 In fuzzy dark matter (FDM), soliton cores form at the center of virialized halos. Previous studies predict a scaling relation between the core mass and halo mass due to the scaling symmetry of the Schrödinger-Poisson equation and the uncertainty principle. However, the simulation results deviate from this scaling relation for massive halos without an explanation. In this work, we first show that this inconsistency is partly due to insufficient simulation resolution for resolving the FDM quantum pressure, leading to unphysical compression of both halo and soliton. With adequate resolution, the FDM halo in our simulations can coincide very well with a CDM counterpart, and the soliton mass becomes closer to the expected value. In our subsequent analysis, we enhance the accuracy of the gravitational potential by substituting the top-hat model with the widely accepted NFW (Navarro-Frenk-White) profile. Furthermore, by analyzing the inner part of the halos, we find that the isothermal assumption is not valid for massive halos, resulting in an under-prediction of soliton mass. Additionally, it has been observed that there exists a constant temperature differential between the core and its surrounding halo. This phenomenon may be attributed to the inherent characteristics of the soliton. These new findings pave the way for revising the core-halo relation and improving our understanding of soliton formation in the early universe. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/89861 |
DOI: | 10.6342/NTU202303346 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 物理學系 |
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