COSMOS天区星系团的BO效应和CM关系

发布时间：2018-05-29 09:41

  本文选题：星系 + 星系团　； 参考：《南京师范大学》2014年硕士论文

【摘要】：星系团是宇宙中最大的自引力束缚系统,是宇宙大尺度结构的重要示踪物,是研究星系演化过程及其与环境相互作用的“实验室”。在众多的星系巡天项目中,COSMOS巡天是最重要的深度巡天项目之一,其覆盖了赤道附近两平方度的天区,旨在利用地面和空间的主要大型望远镜设备研究星系的形成、演化及其随宇宙时间(即红移)和大尺度结构环境的变化规律。 Butcher-Oemler效应(简称BO效应)是星系演化研究领域中的重要成果,即星系团中蓝星系所占比例随着红移的增大而增加。本文基于COSMOS天区的测光红移数据,WenHan(2011)[62]得到了一个包含187个星系团的样本,其中包含大量高红移的星系团,非常适合用来研究星系团中的蓝星系比例随红移的演化效应。利用Subaru望远镜的g+、r+和i+星等数据,我们采用了三种颜色判据来挑选蓝星系,均发现星系团中蓝星系的比例随红移显著上升。我们确认了BO效应的存在,还发现其弥散程度和星系团富度有关。 颜色-星等关系(简称CM关系)是指椭圆星系的颜色与绝对星等之间的一种线性关系,反映了早型星系的光谱随星系质量的演化规律。本文主要研究的是这种线性关系是如何随红移变化的,这种变化是否与环境密度有关。本论文采用COSMOS天区中四个红移区间的星系团成员星系和场星系中的早型星系样本,通过对比团星系和场星系的CM关系图,发现随着红移的增加,星系团中早型星系的CM关系有变陡的趋势,而场星系的斜率没有明显的变化趋势。在相同的红移区间中,两者的斜率基本一致,没有发现显著的环境效应。
[Abstract]:The cluster of galaxies is the largest self-gravity binding system in the universe and an important tracer of the large-scale structure of the universe. It is also a "laboratory" for studying the evolution of galaxies and their interaction with the environment. Among the many galactic surveys, cosmos is one of the most important deep surveys, covering two square degrees near the equator to study the formation of galaxies using major telescopes on the ground and in space. Evolution and its variation with cosmic time (i.e. redshift) and large scale structural environment. The Butcher-Oemler effect (BO effect) is an important achievement in the field of galaxy evolution, that is, the proportion of blue stars in clusters increases with the increase of redshift. In this paper, we have obtained a sample of 187 clusters of galaxies, which contains a large number of clusters of Gao Hong shifts, based on the photometric redshift data of the COSMOS sky region. [62] A sample of 187 clusters is obtained, which is very suitable for studying the evolution of blue star ratio with redshift in clusters. Three color criteria are used to select the blue star system using the data of the Subaru telescope, such as g r and I stars. It is found that the proportion of blue stars in the cluster increases significantly with the redshift. We have confirmed the existence of BO effect and found that the dispersion degree is related to the rich degree of galaxy cluster. The color-star relation (CM) is a linear relationship between the color of elliptical galaxies and the absolute magnitude, which reflects the evolution of the spectrum of early type galaxies with the mass of galaxies. This paper mainly studies how the linear relation changes with the red shift and whether the change is related to the environmental density. In this paper, by comparing the CM relationship between cluster galaxies and field galaxies in the four red-shift regions of COSMOS, we find that with the increase of redshift, we find that, The CM relation of the early type galaxies in the cluster tends to become steeper, but the slope of the field galaxies has no obvious change trend. In the same red-shift range, the slope of the two is basically the same, and no significant environmental effects are found.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P157.8
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本文编号：1950402