X-ray/UV/optical Variability and Mapping the Inner Structures of Active Galactic Nuclei.

X 射线/紫外线/光学变化和绘制活动星系核的内部结构。

• 批准号: 2114738
• 金额: --
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2114738
• 关键词: ray; UV; optical; Variability; Mapping

The origin of UV and optical variability from Active Galactic Nuclei (AGN) is not well understood. It may be caused by reprocessing of X-ray emission, coming from very near to the central supermassive black hole (SMBH), by the surrounding accretion disc and broad line region (BLR) gas. Alternatively it might be caused by accretion rate fluctuations in the disc. These possibilities can be tested by measuring the time lags between the X-ray emission and the emission in the UV and optical bands. Different physical scenarios result in different time lag patterns. In the reprocessing scenario, the lags map out the temperature structure of the accretion disc and the geometry of the surrounding gas, in a process known as 'reverberation mapping'. These structure are far too small to map by direct imaging or any other method.Southampton is one of the major world research groups in the study of AGN variability and we lead many of the largest X-ray/UV/optical monitoring programmes, eg using the Swift multiwaveband observatory and the XMM-Newton X-ray/UV observatory. In particular, a huge observational program with Swift will be complete by early 2018, ideally timed for a new student.The current project consists of both observation and computer modelling. The successful student will analyse these world-leading datasets to map out the inner structures of AGN and will also build a computer model of the expected emission from the accretion disc and BLR gas. By comparing observation with theory we will determine the inner geometry of AGN, including both the X-ray source geometry and that of the inner part of the accretion disc.

活动星系核（AGN）的紫外和光学变化的起源还没有很好的理解。它可能是由来自非常接近中心超大质量黑洞（SMBH）的X射线辐射，通过周围的吸积盘和宽线区（BLR）气体的再加工引起的。或者，它可能是由盘中的吸积率波动引起的。这些可能性可以通过测量X射线发射与紫外和光学波段发射之间的时间滞后来测试。不同的物理情景导致不同的时滞模式。在后处理方案中，滞后映射出吸积盘的温度结构和周围气体的几何形状，这一过程被称为“混响映射”。南安普顿是世界上研究活动星系核变化的主要研究小组之一，我们领导了许多最大的X射线/紫外线/光学监测计划，例如使用斯威夫特多波段天文台和XMM-牛顿X射线/紫外线天文台。特别是，Swift的一个大型观测项目将于2018年初完成，这是一个新学生的理想时间。目前的项目包括观测和计算机建模。成功的学生将分析这些世界领先的数据集，以绘制出AGN的内部结构，并将建立一个来自吸积盘和BLR气体的预期发射的计算机模型。通过观测与理论的比较，我们将确定活动星系核的内部几何结构，包括X射线源的几何结构和吸积盘内部的几何结构。