【作者】 彭志欣；

【导师】 顾秋生； 陈燕梅；

【作者基本信息】 南京大学 ， 天体物理学， 2013， 博士

【摘要】 光谱中的强发射线是活动星系核最显着的观测特征,通过发射线来研究活动星系核的物理性质是应用最广泛的方法,为理解活动星系核的本质提供了大量的信息。不论是宽发射线还是窄发射线,都是通过来自活动星系核中心能源的高能光子光致电离产生的,因此都能用于研究活动星系核。发射线的各种特征(流量强度、等值宽度、速度偏移等等)与活动星系核的各方面性质之间存在各种各样的联系,这方面的研究已经取得了巨大的成果。随着观测设备和手段的不断更新,利用发射线来研究活动星系核的物理性质也更加的深入,范围也更加的广泛。本论文主要集中在利用λλ4959,5007窄发射线来研究活动星系核的某些特殊天体物理现象,包括双活动星系核的存在和性质、活动星系核外流与核活动的联系以及与宿主星系的联系和演化。这些都是近十年来在星系的形成和演化中取得的最新进展。对于双活动星系核,已经发现了相当数量的实例,开始了大规模的寻找。活动星系核的外流,或反馈,已经被认为是活动星系核活动与宿主星系演化过程中不可缺少的机制。论文的具体结构如下：第一章是活动星系核的概述,简单介绍了活动星系核标准模型和发射线的产生区域,并介绍了宇宙学模型下活动星系核与宿主星系之间的关系,以及我们研究的重要性和意义。还介绍了窄发射线的复杂结构和在研究中的重要作用。同时也简单介绍了SDSS这个巡天项目。第二章主要介绍了我们找到了一个双活动星系核的候选体。我们对宽线类星体SDSS J1425+3231这个源的光谱进行了分析,扣除连续谱后得到的发射线明显具有双峰结构,然后我们仔细解析了窄发射线的双峰结构,在此基础上估算了中心黑洞的质量,并分析了双峰窄发射线的起源,最后提出这是一个双活动星系核的候选体。此外了还讨论了发现双活动星系核的方法和可能性。第三章主要讨论对活动星系核中外流的统计研究。我们对具有蓝移不对称窄发射线的2型活动星系核样本进行发射线分析,发现窄发射线两个成分的流量存在很强的相关,但没发现窄发射线蓝移线翼偏移速度与星系的物理性质之间存在联系；还比较了1型、2型活动星系核窄发射线蓝移线翼的性质,发现1型活动星系核具有更高的蓝移线翼速度,线翼成分更靠近活动星系核中心。最后提出窄发射线蓝移的宽线翼来自于活动星系核的外流,和现有的结果一致。第四章是我们工作的简单总结和对未来工作的展望,以及对拓展我们工作应用的设想。更多还原

【Abstract】 Strong emission lines in spectrum is the prominent observation feature of ac-tive galactic nuclei (AGNs). Using emission lines to study the physical properties of AGNs is the most widely used method, which provide numerous information to understand the nature of AGNs. Whether broad emission lines or narrow emis-sion lines, originated from ionization of gases by high-energy photons from center nuclear, can be used to infer AGNs properties. There are a variety of links be-tween the characteristics of the emission lines (such as flux intensity, equivalent width, and speed offset) and the various natures of AGNs. Many tremendous achievements in this field have been made. With the help of constantly updated observation equipment and approaches, using the emission lines to study the physical properties of AGNs become more deeper and more wider.This thesis mainly focused on the studies of some special astrophysical phe-nomena of AGNs, including the existence and the nature of dual AGNs, the rela-tionships between outflows of AGNs and nuclear activities, and the host galaxy evolution, by analysis of [O Ⅲ λλ4959,5007narrow emission lines. These are the latest progress in the formation and evolution of galaxies over the past decade. For dual AGNs, it has been found a considerable number of instances, and there are some large-scale survey for it. While outflow of AGNs, or feedback, has been considered to be an indispensable mechanism in AGNs activity and the evolution of the host galaxies. The paper is organized as follows:The first Chapter is a review of AGNs, including the standard model and the regions in which emission lines originated. We then describe the relationship between AGNs and their host galaxies in the hierarchical cosmological model, as well as the significance of our study. Furthermore, We briefly depict the complex structure of the [O Ⅲ] narrow emission line and its significance for AGN research, as well as the SDSS sky survey project.In Chapter2, we introduce a candidate for dual AGNs. We analyze the optical spectrum of type1QSO SDSS J1425+3231. After subtracting the contin-uum spectrum, its narrow emission lines such as [OⅢ] λλ4959,5007are double peaked. Then we carefully fit the double-peaked [OⅢ]lines using multiple Gaus-sian components. The black hole mass is estimated from the fitting parameters, and the origin of the double-peaked narrow emission lines is discussed. At last we suggest this QSO might be a dual AGN system. We also discuss the method and the possibility of finding dual AGNs.The third Chapter focuses on statistical studies of outflows in AGNs. We explore the asymmetric behavior of the narrow emission line [O Ⅲ] A5007in a type2AGNs sample with the blue shift narrow emission lines. It shows that there exists a strong correlation between the flux of core component and the wing. However, no correlation is found between the blueshift velocity of the broad wing and the host properties, such as Eddington ratio. We also compare the broad blueshift wing component in type1and type2AGNs. A higher blueshift velocity in type1AGNs sample indicates that the blueshift wing component is located nearer to the center of AGN. Finally, the broad blueshift wing of narrow emission line is suggested to be caused by the outflow of AGN, it is consistent with previous researches.Chapter four summarizes our works and presents ideas for future research. The prospect of a broadened application of our works has been proposed too.更多还原