活动星系核软X射线强烈光变样本的研究

发布时间：2018-08-15 17:26

【摘要】：AGN是宇宙中最明亮的天体,其主要特征之一就是具有显著的光变。其辐射主要源自中心的超大质量黑洞的气体吸积盘。在相对靠近中心黑洞的区域有宽线区,活动星系核光谱中的宽发射线就来自这里。再向外则是尺度相对较大的窄线区,这里贡献了活动星系核光谱中的窄发射线。在吸积盘和宽线区周围,有一个尘埃环结构。由于尘埃环会对宽线区产生遮蔽,导致AGN在不同观测视角下有不同的光谱特性。X射线来自于靠近中心黑洞的很小尺度的区域,其光变与黑洞和吸积盘的状态有密切联系。因此活动星系核X射线光变样本的研究,提供给我们一个了解和验证其中心超大质量黑洞及其周边的物理图像的途径,也有助于我们验证现有的一些理论模型。本文主要介绍了我们建立的一个在软X射线具有强烈光变的活动星系核的样本。通常活动星系核在不同波段都有显著光变,我们的工作主要关注软X射线波段的光变。软X射线波段的光变可能是由于活动星系核本征X射线的光变导致的,也可能是由于视线方向的吸收变化导致的。之前对软X射线强烈光变的系统研究比较少,我们利用ROSAT望远镜在90/91年的巡天数据以及XMM望远镜的2000-2009年的数据,匹配得到了在软X射线波段流量变化大于10倍的13个源的一个样本。根据这个样本,搜集整理了其中已被研究讨论过的源的信息。对于剩下那些没有以往研究的源,分析讨论其XMM-Newoton的光谱。最终试图给出样本中每个源可能的光变原因。在第一章中,我们简要地对活动星系核以及其光变研究和我们所做的工作做了一个概述,包括介绍了活动星系核的一些基本性质及其分类；活动星系核的光变性质,一些用于研究光变的工具以及目前活动星系核光变研究的结果；已有的关于活动星系核光变的模型；第二和第三章中,主要阐述了我们的工作,包括分详细说明了我们如何匹配ROSAT和XMM的星表得到最终的13个源和利用得到的13个源的样本,参考以往研究并利用其XMM光谱拟合,逐个源分析其光变原因的可能性；在最后一章中,我们总结了之前所有工作,给出个各个源光变最有可能的原因作为结论,方便今后研究做为参考。
[Abstract]:AGN is the brightest object in the universe. The radiation comes mainly from the gas accretion disk of the supermassive black hole at the center. There are wide lines in the region relatively close to the central black hole, where the broad emission lines in the active galaxy nucleus spectrum come from. Then out is the relatively large narrow line region, which contributes the narrow emission line in the AGNs spectrum. There is a dust ring structure around the accretion disk and wide line area. Because the dust ring will cover the wide line region, the AGN has different spectral characteristics under different observational angles. The X-ray comes from a very small area near the central black hole, and its light change is closely related to the state of the black hole and accretion disk. Therefore, the study of X-ray light samples of active galactic nuclei provides us with a way to understand and verify the physical images of its supermassive black holes in and around them, and also helps us to verify some existing theoretical models. In this paper, we introduce a sample of active galactic nuclei with strong light variation in soft X-ray. In general, active galactic nuclei (AGNs) show significant light changes in different wavelengths, and our work focuses on the soft X-ray band. The light change in soft X ray band may be caused by the intrinsic X ray change of active galaxy nucleus, or by the absorption change in the direction of line of sight. There has been less research on soft X-ray intense light change systems before. We use the ROSAT telescope's survey data for 90 / 91 and the XMM telescope's data for 2000-2009. A sample of 13 sources with a flux variation of more than 10 times in the soft X-ray band was obtained by matching. Based on this sample, information on the sources discussed in the study was collected and collated. For the remaining sources that have not been previously studied, the XMM-Newoton spectra are analyzed and discussed. Finally, an attempt is made to give the possible causes of light variation for each source in the sample. In the first chapter, we give a brief overview of the study of AGNs and their photoluminescence, including some basic properties of AGNs and their classification, and the photonic properties of AGNs. Some of the tools used to study light change and the results of current studies of active galactic nuclei; existing models of active galactic nuclear light change; and chapters II and III, focusing on our work, Including the detailed description of how we match the catalog of ROSAT and XMM to obtain the final 13 sources and 13 source samples, referring to previous studies and using its XMM spectrum fitting, the possibility of analyzing the cause of light change is analyzed one by one. In the last chapter, we summarize all the previous work, and give a conclusion of the most probable reason for the source light change, which is convenient for future research as a reference.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P157.6;P172.2

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