The first quasars and super-massive black holes

第一个类星体和超大质量黑洞

• 批准号: 1708258
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1708258
• 关键词: first; quasars; super; massive; black

Quasars, which are powered by material falling into super-massive black holes, have been discovered when the Universe was just 5% of its current age (of 13.8 billion years). It is generally accepted that these black holes have masses in the range 10^9-10^10 Solar masses despite the fact that there is no known way to form and grow such objects in the available cosmological time.The first part of this project is to use the results from surveys of distant quasars to determine their population and, in particular, how it is evolving with cosmic time. The observed numbers/properties of high-redshift quasars will be combined with other constraints on the super-massive black hole population, using Bayesian inference to combine the available information.The second part of this project concerns the black holes themselves: it is very difficult to explain the formation of black holes of > 10^9 Solar masses in less than a billion years, but another possibility is that they are not actually so massive - their mass estimates come from extrapolating an imperfect empirical correlation established from a different population of quasars which, typically, have much lower mass black holes, and the current approaches to this problem tend to ignore the various significant sources of uncertainty; the approach here will be to go back to the original measurements and then use a hierarchical Bayesian model to link the black hole estimates to the actual astronomical observations.

类星体由落入超大质量黑洞的物质提供动力，在宇宙年龄仅为当前年龄（138 亿年）的 5% 时就被发现了。人们普遍认为这些黑洞的质量在 10^9-10^10 太阳质量范围内，尽管事实上没有已知的方法可以在可用的宇宙时间内形成和生长此类物体。该项目的第一部分是利用对遥远类星体的调查结果来确定它们的数量，特别是确定它们如何随宇宙时间演化。观测到的高红移类星体的数量/属性将与超大质量黑洞种群的其他约束相结合，使用贝叶斯推理来结合可用的信息。该项目的第二部分涉及黑洞本身：这是非常困难的来解释在不到 10 亿年的时间里形成大于 10^9 太阳质量的黑洞，但另一种可能性是它们实际上并没有那么大——它们的质量估计来自于根据不同的黑洞群体建立的不完美经验相关性的推断。类星体通常具有质量低得多的黑洞，而当前解决此问题的方法往往忽略了各种重要的不确定性来源；这里的方法是返回原始测量结果，然后使用分层贝叶斯模型将黑洞估计与实际天文观测联系起来。