星系中心重質量黑洞之動力學; Dynamics of Galactic Centers with Massive Black Holes

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/6038

Title:	星系中心重質量黑洞之動力學;Dynamics of Galactic Centers with Massive Black Holes
Authors:	陳宜貞;I-Cheng Chen
Contributors:	天文研究所
Keywords:	星系中心;重質量黑洞;動力學;galactic centers;massive black holes;dynamics
Date:	2004-07-06
Issue Date:	2009-09-22 10:12:16 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	近年來，星系形成與演化一直是天文學家們相當感興趣的課題，橢圓星系（elliptical galaxies）有可能是由螺旋星系（spiral galaxies）相互合併演化而成。假若兩個星系各自包含一個中心巨大質量黑洞（massive black hole），則合併的結果，很可能會在星系合併的中心區域形成巨大質量雙黑洞的動力學系統。Lauer等天文學家在2002年使用哈伯太空望遠鏡的觀測資料，找到六個橢圓星系，其表面亮度(surface brightness)並非從星系中心往外單調遞減。這些複雜的中心結構，很有可能就是由於星系中心包含雙黑洞系統，影響了恆星的分佈所造成的。我們利用解析近似(semi-analytic approach)的方法來討論星系中心包含雙黑洞系統的動力學，並推測星系中心附近恆星可能的軌道。接著再以更實際的模型，來模擬恆星的運動，討論不同軌道半徑的雙黑洞，對星系中心恆星分佈的影響。並證實星系中心某些區域恆星密度的減少與雙黑洞的存在有關。最後討論巨大質量黑洞在星系合併的最後階段，掉進星系中心的過程對於恆星分佈造成的影響。我們的模擬結果支持「星系中心表面亮度非單調遞減，可能是由巨大質量雙黑洞的運動所造成」之假設。 The formation and evolution of galaxies are always a popularly discussed problem. One suggestion is that the elliptical galaxies might form from the merging of spiral galaxies. Begelman et al. (1980) argued that galaxies should occasionally merge, and the massive black hole binaries may be formed by merging of two galaxies, with each contains a massive black hole at its nuclei. Lauer et al. (2002) used HST WFPC2 camera to identify six elliptical galaxies with local minimum of the surface brightness around their centers. The complicated structures of galactic centers might be formed by the dynamical effect of massive black hole binaries at their centers. In this thesis, we study the dynamics of galactic centers with massive black holes. First, we use the semi-analytic approach to study the possible stellar orbits around the galactic centers. Secondly, more practical models are used to simulate the motions of stars. We discuss the evolution of stellar distribution with different orbital radii of black holes. Thus, we see that the existence of black holes will influence the stellar distribution of galactic centers. Finally, we use the model with one massive black hole sinking toward the galactic center, to investigate the possible orbits of the black hole and the stellar distribution. The results of our simulations support the hypothesis that the non-monotonic decrease of the surface brightness at the galactic centers may due to the motions of massive black hole binaries.
Appears in Collections:	[Graduate Institute of Astronomy] Electronic Thesis & Dissertation

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