对SDSS DR7中“星系对”选择标准的探讨

发布时间：2019-03-14 20:29

【摘要】：星系间的相互作用及合并对于星系的形成和演化有着十分重要的作用,它们自身也是天文观测和研究中引人注目的物体。从理论上说,星系的相互作用和合并对星系的演化起着主要的推动作用,它们也影响星系的形态和光谱特征、气体动力学、高能过程和核反应过程。基于数值模拟结果说明椭圆星系的形成是由于漩涡星系间的相互作用最早由Toomre(1997)[38]提出,Schweizer(1999)对于合并过程对于早期星系盘和椭圆星系的重要性也做过相应研究。但由于数据的不同和研究者所采用的不同的“星系对”的选择标准,因而他们的样本在统计结果上存在部分差异,因而得到的研究结果也不完全一致。本文基于Allam(2004)[1]和Ellison[8]-[12]等人的工作,分别从SDSSDR7的测光和光谱观测的数据库中以两个不同“星系对”的选择标准证认出两个高质量相互作用的“星系对”样本。随后,本文对这两个星系对样本中的星系对进行了交叉证认,分析了两个样本中部分“星系对”样本的异同并探讨产生这些差异的原因。此外,本文还通过从SDSS的数据库中下载该星系的各种测光数据和光谱数据,并且还在相应的catalog中找到并收集了对应星系的金属丰度,恒星形成率等数据,方便随后对这两个样本的性质进行统计上的分析。另外,本文根据样本中真实星系的红移、星等、半径的分布模拟了一批星系,并使用相同的星系对标准来选取其中的星系对样本,以此来考察两个样本的投影效应和检测样本的完备性。
[Abstract]:Intergalactic interactions and mergers play a very important role in the formation and evolution of galaxies. They are also eye-catching objects in astronomical observation and research. Theoretically, the interaction and merging of galaxies play an important role in the evolution of galaxies. They also affect the morphology and spectral characteristics of galaxies, gas dynamics, high energy processes and nuclear reactions. Based on the numerical simulation results, it is shown that the formation of elliptical galaxies is due to the interaction between spiral galaxies, which was first proposed by Toomre (1997) [38] for the importance of the merging process for early galactic disks and elliptical galaxies. However, due to the different data and the different selection criteria of "galaxy pairs" adopted by the researchers, there are some differences in the statistical results of their samples, so the results obtained are not exactly the same. Based on the work of Allam (2004) [1] and Ellison [8]-[12], According to the selection criteria of two different "galactic pairs", two high-quality interacting "galactic pairs" samples were identified from SDSSDR7's database of photometric and spectral observations respectively. Then, this paper cross-identifies the galaxy pairs of the two galaxies, analyzes the similarities and differences of some "galaxy pairs" in the two samples, and discusses the reasons for these differences. In addition, various photometric and spectral data of the galaxy are downloaded from SDSS's database, and the corresponding metallicity, star formation rate and other data of the corresponding galaxies are found and collected in the corresponding catalog. It is convenient to analyze the properties of these two samples statistically. In addition, according to the distribution of the red shift, magnitude and radius of the real galaxies in the sample, this paper simulates a number of galaxies, and uses the same pair of galaxies to select the samples of the pairs of galaxies among them. In this way, the projection effect of two samples and the completeness of the test samples are investigated.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P152

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