星系团内成员星系的恒星形成历史研究

发布时间：2018-05-26 01:28

本文选题：星系 + 星系团　；参考：《南京师范大学》2011年硕士论文

【摘要】：研究星系的恒星形成性质已成为近十年来河外天体物理学最热门的研究领域之一。探索星系团中成员星系的恒星形成性质及其与星系形态、环境以及其他一些星系物理特性之间的关系,有助于我们了解星系的形成和演化,从而了解整个宇宙的形成和演化的历史。多波段观测数据表明,位于南半天区的cD星系团A85(z=0.055)是一个处于并合中的星系团。基于Sloan Digital Sky Survey (SDSS)提供的242个成员星系的光谱,我们利用演化星族合成代码STARLIGHT,获得了这些星系的恒星形成历史,由此分析星系的恒星形成性质与局域空间密度之间的关系。我们发现：随着星系局域而密度的增加,星系的金属丰度也在增加,星系的年龄相对较大；在整个恒星形成历史时期,密度高的区域星系的恒星形成率高；在最近的24.5Myr,低密度区域中星系的恒星形成率相对较高,高密度区域的星系中则几乎没有发现恒星形成；密度低的区域星系特征恒星形成率总是大于密度高区域的星系特征恒星形成率。此外,质量越大的星系在最近24.5Myr的特征恒星形成率越小；质量越小的星系最近的特征恒星形成率越高。本文还对星系团A2255中成员星系的恒星形成性质做了对比研究。我们利用基于连续谱拟合的STARLIGHT方法对来自SDSS的数据做了处理,与利用兼顾发射线与连续谱的MPA/JHU方法得出的数据做了对比性研究。我们发现：(1)这两种方法估计出的恒星质量非常一致；(2) STARLIGHT获得的24.5Myr内的特征恒星形成率与MPA/JHU估计的特征恒星形成率也基本吻合。(3)我们还比较了两种方法获得的特征恒星形成率随着投影距离之间的关系,得到了与过去研究一致的环境效应。(4)由STARLIGHT给出的光度权重下的平均恒星年龄和连续谱参数Dn(4000)具有很强的相关性。(5)利用STARLIGHT获得的金属丰度和MPA/JHU获得的恒星质量参数,验证了前人提出的星系金属丰度和星系质量的相关性。
[Abstract]:The study of star formation in galaxies has become one of the hottest research fields in extragalactic astrophysics in recent ten years. Exploring the star forming properties of galaxies that are members of the cluster and their relationship with the shape, environment and other physical properties of galaxies will help us to understand the formation and evolution of galaxies. In order to understand the formation and evolution of the entire history of the universe. The multi-band observations show that the CD cluster A85ZN 0.055, located in the southern half day region, is a cluster in the mergence. Based on the spectra of 242 member galaxies provided by Sloan Digital Sky Survey / SDSS, the star formation history of these galaxies is obtained by using the evolutionary star family synthesis code STARLIGHT.The relationship between star formation properties and local spatial density of galaxies is analyzed. We find that with the increase of the local and density of galaxies, the metal abundance of galaxies increases, and the age of galaxies is relatively large, and the high density regional galaxies have high star formation rate during the whole history of star formation. In the most recent area of 24.5Myr, star formation rates are relatively high in galaxies in low-density regions, and almost no star formation is found in galaxies in high-density regions. The characteristic star formation rate of low density region is always higher than that of high density region. In addition, the higher the mass, the smaller the characteristic star formation rate of the nearest 24.5Myr, and the higher the nearest characteristic star formation rate of the smaller mass galaxy. The star formation properties of galaxies in cluster A 2255 are also studied in this paper. The STARLIGHT method based on continuous spectrum fitting is used to process the data from SDSS, and a comparative study is made with the data obtained by using the MPA/JHU method which combines the emission line and the continuous spectrum. We find that the two methods estimate the star mass is very consistent) the characteristic star formation rate in 24.5Myr obtained by STARLIGHT is also basically consistent with the characteristic star formation rate estimated by MPA/JHU.) We also compare the characteristics obtained by the two methods. The relationship between star formation rate and projection distance, The results show that the environmental effects consistent with previous studies, such as the average star age and the continuous spectral parameter Dnn4 given by STARLIGHT, have a strong correlation. 5) the metal abundance obtained by STARLIGHT and the stellar mass parameters obtained by MPA/JHU are highly correlated. The correlation between metallic abundance and galactic mass was verified.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：P152

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