卫星星系动力学状态对星系属性的依赖

发布时间：2018-02-02 15:13

本文关键词： 暗晕质量星系群卫星星系速度弥散中央星系属性卫星星系属性　出处：《中国科学技术大学》2016年硕士论文　论文类型：学位论文

【摘要】：现在的星系形成理论认为星系形成于暗晕之中,暗晕的属性对星系的形成与演化有主导性的影响。基于SDSS数据我们详细研究了卫星星系动力学状态对卫星星系属性的依赖。其中卫星星系动力学是测量星系所在暗晕质量的重要方法。假设中央星系质量和卫星星系速度弥撒之间有着一对一的相关性,我们采用一种自适应方法从星系样本中挑选出中央星系及其卫星星系。我们研究中央星系质量和卫星星系速度弥散的关系,并探讨速度弥散和中央星系属性(颜色和聚集度)与卫星星系属性(质量、颜色、聚集度和相对中央星系的距离)的关系。和之前的研究一致,卫星星系速度弥散随着中央星系质量增大而增大。一般来说,红(或早型)中央星系所在星系群的速度弥散比蓝(或晚型)中央星系要偏大。在红(或早型)中央星系周围,卫星星系的速度弥散和其质量之间没有明显关联,但是在蓝(或晚型)中央星系周围,卫星星系质量越大,速度弥散越大;红卫星星系的速度弥散要比蓝卫星星系大:早型卫星星系和晚型卫星星系之间没有显著的速度弥散差异;在红(或早型)中央星系周围,距离中央星系较近的卫星星系速度弥散较大,不过对于蓝(或晚型)中央星系,没有发现类似特征。总的来说,卫星星系属性和其速度弥散之间的关系相对较弱。这一关系存在两种可能的解释。一种可能是,卫星星系属性和所在暗晕质量之间存在相关性;另一种可能是,卫星星系属性和暗晕质量无关,和其动力学状态直接关联。为了区分这两种可能的解释,我们挑选了一类特殊的星系群样本来研究。这类星系群同时包含两种对应性质的卫星星系,从而有效排除暗晕质量不同的效应。我们发现在这类特殊的星系群中,无论中央星系属性如何,卫星星系的速度弥散和其质量之间没有相关性,和其位置有一定的弱相关,距中央星系越近速度弥散越大。红卫星星系的速度弥散要比蓝卫星星系小,和整体样本中的结果相反。这些红卫星星系的质量要比蓝卫星星系大,到中央星系的距离也比蓝卫星星系小,这可能预示着一些复杂的物理过程。去除了这类特殊的星系群后,我们又考察了只包含某类性质卫星星系的星系群的卫星星系动力学状态。我们发现,无论中央星系属性如何,卫星星系质量大的速度弥散大,而且这一结果的显著度要明显高于整体样本。同样的,红卫星星系的速度弥散要比蓝卫星星系大。由于统计上红卫星星系的质量要大于蓝卫星星系,速度弥散对于质量和颜色的依赖本质上可能是一致的。这强烈表明,给定中央星系属性后,暗晕质量和卫星星系质量之间存在系统的关联,卫星星系质量越大,暗晕质量越大。可见,卫星星系质量也是一个影响暗晕质量的重要参数。
[Abstract]:The current theory of galaxy formation is that galaxies are formed in dark halos. The properties of dark halos have a dominant influence on the formation and evolution of galaxies. Based on SDSS data, we have studied the dependence of satellite galactic dynamics on satellite galactic properties in detail, in which satellite galactic dynamics is a measurement star. It is assumed that there is a one-to-one correlation between the mass of the central galaxy and the velocity mass of the satellite galaxy. We use an adaptive method to select central galaxies and their satellite galaxies from galaxy samples. We study the relationship between the mass of central galaxies and the velocity dispersion of satellite galaxies. The relationship between velocity dispersion, central galaxy properties (color and aggregation) and satellite galaxy attributes (mass, color, aggregation and distance to central galaxies) is discussed. The velocity dispersion of satellite galaxies increases with the mass of central galaxies. Red (or early) central galaxies are dispersed more rapidly than blue (or late) central galaxies. Around red (or early) central galaxies. There is no obvious correlation between the velocity dispersion of satellite galaxies and their mass, but the larger the mass of satellite galaxies, the greater the velocity around the blue (or late) central galaxies. The velocity dispersion of red satellite galaxies is larger than that of blue satellite galaxies: there is no significant difference in velocity dispersion between early satellite galaxies and late satellite galaxies; Satellite galaxies closer to red (or early) central galaxies spread faster, but no similar features were found in blue (or late) central galaxies. The relation between satellite galaxy attribute and its velocity dispersion is relatively weak. There are two possible explanations for this relationship. One possibility is that there is a correlation between satellite galaxy attribute and the mass of the dark halo in which satellite galaxy is located. Another possibility is that satellite galaxy properties are independent of the mass of dark halos and are directly related to their dynamic states in order to distinguish between the two possible explanations. We have selected a sample of a particular cluster of galaxies, which contains two satellite galaxies with corresponding properties. We find that there is no correlation between the velocity dispersion of satellite galaxies and the mass of satellite galaxies, regardless of the properties of central galaxies. There is a weak correlation with its location, and the closer it is to the central galaxy, the larger the velocity is. The redsatellite galaxy has a smaller velocity than the blue satellite galaxy. Contrary to the results in the overall sample, these red satellite galaxies are larger in mass than blue satellite galaxies, and smaller in distance from central galaxies than blue satellite galaxies. This may indicate some complex physical processes. After removing this particular cluster of galaxies, we have examined the dynamics of satellite galaxies with only one type of satellite galaxies. Regardless of the nature of the central galaxy, the mass of the satellite galaxy spreads rapidly, and the result is significantly more significant than the sample as a whole. Red satellite galaxies spread faster than blue satellite galaxies because the red satellite galaxies were statistically larger in mass than blue satellite galaxies. The dependence of velocity dispersion on mass and color may be essentially the same, which strongly indicates that there is a systematic correlation between the mass of dark halo and the mass of satellite galaxies, and the larger the mass of satellite galaxies, the greater the mass of satellite galaxies. Therefore, the mass of satellite galaxies is also an important parameter affecting the mass of dark halos.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P152

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