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.

活跃银河核（AGN）的紫外线的起源和光学变异性尚不清楚。这可能是由于X射线发射的重新处理，来自周围的积聚盘和宽线区域（BLR）气体从非常靠近中央超级黑洞（SMBH）的重新处理。另外，它可能是由于盘中的积聚率波动引起的。可以通过测量X射线发射与紫外线和光条带之间的时间滞后来测试这些可能性。不同的物理场景导致不同的时间滞后模式。在重新处理的情况下，滞后绘制了积聚盘的温度结构和周围气体的几何形状，这是一个称为“回响映射”的过程。这些结构太小了，无法通过直接成像或任何其他方法绘制。Southampton是AGN变异性研究的主要世界研究小组之一，我们领导着许多最大的X射线/UV/光学监测程序，例如，使用Swift MultiwaveBand Perservatory和XMM-Newton X-Ray/UV overeratory。特别是，在2018年初之前将完成一个庞大的与Swift的观察计划，理想情况下是新学生的时间。当前的项目包括观察和计算机建模。成功的学生将分析这些世界领先的数据集，以绘制AGN的内部结构，还将建立一种从积聚光盘和BLR气体中预期排放的计算机模型。通过将观察结果与理论进行比较，我们将确定AGN的内部几何形状，包括X射线源几何形状和积聚盘的内部几何形状。