Unravelling accretion flows in AGN and binaries using their complex variability patterns

利用活动星系核和双星复杂的变异模式来揭示吸积流

• 批准号: 1952894
• 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: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1952894
• 关键词: Unravelling; accretion; flows; AGN; binaries

Accretion onto black holes proceeds according to a well observed phenomenology, however, little of the details are presently well understood. One of the least understood aspects is the prevalence and nature of high frequency quasi-periodic oscillations (QPOs), seen at high accretion rates in black hole binaries (BHBs) and only two active galactic nuclei (AGN). The frequency of these QPOs indicates that they likely originate in the region of strong gravity close to the black hole, where effects of general relativity are dominant. Given the mass scaling of the QPO frequencies, AGN allow for a much better (protracted) view of these QPOs yet are extreme rarities. Part 1 of the project is to search the XMM-Newton datasets of the brightest AGN (the PG QSOs) for QPO candidates by energy-slicing the data and by applying a new algorithm to detect coherent signals in noisy data. This technique will also be extended to the vast archives on BHBs (principally RXTE) in an effort to discover more QPOs, understand their prevalence and the nature of the sources when they appear. The latter part of the project will also involve use of the covariance spectrum to unravel how changes in the underlying components of emission may be responsible for the appearance of these QPOs.

吸积到黑洞的过程中，根据一个良好的观察到的现象学，然而，很少的细节是目前很好地理解。最不了解的方面之一是高频准周期振荡（QPO）的流行和性质，在黑洞双星（BHB）和只有两个活动星系核（AGN）的高吸积率中观察到。这些QPO的频率表明它们可能起源于黑洞附近的强引力区域，在那里广义相对论的影响占主导地位。鉴于QPO频率的质量缩放，AGN允许更好地（延长）查看这些QPO，但非常罕见。该项目的第一部分是通过对数据进行能量切片和应用一种新的算法来检测噪声数据中的相干信号，来搜索最亮活动星系核（PG类星体）的XMM-牛顿数据集以寻找QPO候选者。这项技术也将扩展到BHB（主要是RXTE）的大量档案中，以努力发现更多的QPO，了解它们的流行程度以及它们出现时来源的性质。该项目的后半部分还将涉及使用协方差谱来揭示排放的基本成分的变化如何可能导致这些QPO的出现。