| 摘要 | 高红移类星体的是用于探索早期宇宙最有力的工具之一,对它们的观测研究为我们了解宇宙再电离、星系与黑洞的演化、星系际介质的分布等具有非常重要的科学意义。本论文依托中国科学院云南天文台丽江观测站的2.4米望远镜参与到这一国际前沿课题的研究,并且以该望远镜所观测到的具备特殊性质的高红移类星体作为突破口,对该领域的若干方面进行相关的研究和探讨。第一章介绍了活动星系核(AGN)的研究历史和作用,并按照红移由高到低的顺序介绍了类星体的研究现状和最新进展、所带来的问题和挑战,最后重点介绍本论文的核心――特殊的高红移类星体。第二章介绍了开展本论文研究所依赖的观测平台和方法,尤其是专门针对暗源天体进行观测方法的优化和创新。第三章主要围绕第一种特殊的高红移类星体――射电噪类星体进行研究。由于我们新发现的一颗红移为5.18的射电噪类星体具备超高光度和超大质量黑洞以及潜在的超爱丁顿特性,其他的国际研究团组马上对该源进行后续的跟踪观测。对这些研究结果进行对比分析后,也激起了我们对超高光度的射电噪类星体进行后续的研究。第四章介绍最近发现的一个红移为6.3的超高光度类星体。迄今为止,这是全世界第一颗使用两米级望远镜发现的红移大于6的类星体。该类星体对现有的黑洞增长理论(爱丁顿受限的吸积过程)提出了巨大的挑战,它还可以被用来开展星系与恒星的形成、星系际介质的形成和分布、复杂吸收线系统以及宇宙再电离等方面的研究。第五章介绍另一种特殊的类星体――宽吸收线类星体,并对超大质量黑洞的活动以及寄主星系的反馈过程进行了研究。第六章以一种新的视角去探讨AGN多样性的“大统一”之路。首先回顾了基于统一模型的AGN的各种分类,重点是射电噪和射电宁静类星体的二分法。通过引入本征矢量平面图的分析方法,进一步探讨了类星体多样性的内在驱动和外在表象,包括超强的能量辐射机制以及具备强相对论性喷流的射电噪类星体与具备亚相对论性外流的宽吸收线类星体之间的关联。最后,我们对本论文中的研究内容和研究结果进行了系统的总结,并对今后的后续研究给出了展望。 |
| 其他摘要 | Observational study of high-redshift quasars provides one of the most powerful probes to explore the early Universe, including the epoch of reionization, the evolution of galaxies and black holes, the formation and distribution of intergalactic medium (IGM) and so on. The thesis is involved in this scientific frontier relying upon the Lijiang 2.4 meter telescope (affiliated to Yunnan Observatories, Chinese Academy of Sciences), and dedicated on investigations and explorations with some peculiar high-redshift quasars observed by the Lijiang 2.4 meter telescope. The first chapter introduces the history of AGN, and the detailed illustrations are focused on the quasar, including the current status and the latest progress, the open questions and corresponding challenges. The observational platform is introduced in Chapter 2, especially the improved and creative methods applied to observations, are introduced in order. In Chapter 3, the first peculiar radio-loud quasar is introduced, in terms of the progress made so far. Due to the special properties of a newly discovered radio-loud quasar at $z=5.18$, such as a SMBH hosted in the center and it is a potentially super-Eddington candidate, this quasar was quickly followed up by other research groups using multi-wavelength facilities. In combination of these observational results, the ongoing study of ultra-luminous radio-loud quasars seems particularly valuable. An ultra-luminous quasar at $z=6.3$ is then introduced in Chapter 4. So far, this is the first time discovering a quasar of redshift larger than 6 with 2-meter telescopes all over the world. It poses a great challenge for the current growth theory of SMBH (Eddington-limited accretion) since it was only 0.9 billion years after the Big Bang. In addition, this quasars can be widely used to explore the formation of galaxies and stars, the distribution of IGM, complex absorption systems and the epoch of reionization, which are partly ongoing within our works. In Chapter 5, we bring up another peculiar type of AGN, the broad absorption line quasar (BALQSO), as a retrospect of SMBH and a new start referring to AGN feedbacks in the early Universe. In chapter 6, a new perspective is introduced to tentatively explore the possible "Grand Unification" of AGN variabilities. We reviewed the AGN classification based on the unified model, especially for the dichotomy of radio-loud and radio-quiet quasars. Through introducing the eigenvector analytical method, some discussions are made to further explore the inherently physical drivers and external phenomena, including the covert process of incredible energy radiation among quasars and the possible connection between relativistic jets and sub-relativistic outflows characterized by RLQs and BALQSOs. At the end, we give a summary of the main results presented in this thesis and an outline on the future study of peculiar high-redshift quasars. |
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