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Research in astrophysics and cosmology at the University of Bristol

布里斯托大学天体物理学和宇宙学研究

基本信息

批准号：
ST/R000700/1
负责人：
Mark Birkinshaw
金额：
$ 98.84万
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Research Grant
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=ST%2FR000700%2F1
关键词：
Research astrophysics cosmology University Bristol

项目摘要

This proposal is for a grant to researchers in the HH Wills Physics Laboratory of the University of Bristol to investigate important questions in astrophysics and cosmology.Much cosmology over the past few years has been based on investigations of clusters of galaxies, and the first project is to ensure the usefulness of clusters by making reliable measurements of their masses. This involves statistically rigorous investigations using several methods on samples of clusters derived from X-ray surveys. The clusters span a wide mass range and are seen over half the age of the Universe, so we also have to take into account how clusters change in time. The X-rays come from hot gas atmospheres held by the clusters - though low in density these atmospheres account for much of the mass of normal matter, and have other detectable effects, for example on the microwave background radiation. Cross-checks with non-X-ray techniques of mass measurement will ensure the reliability of our results.On a smaller scale, we know that individual galaxies also change in time, but there is currently little understanding of how these changes depend on galaxy mass and environment: galaxies of different masses change at different rates, for example. How these processes act with and against one another to build the population of galaxies that we see today is unclear, but the multi-band optical data that we have accumulated allows tests of how galaxies change, and how star formation is fuelled, in the low-redshift Universe. At higher redshift we will look for proto-clusters, which contain the fastest-evolving galaxies, to understand how galaxies evolve during the early growth of the first massive structures.Essentially all massive galaxies contain massive black holes at, or near, their centres, and a third project will investigate how such black holes are able to create intense central radiation sources, and will use the changing brightness and spectrum of X-rays from the inner parts of these systems to study black hole physics and the gas held close to the black hole.A fourth project looks at how the tiny regions in the centres of individual galaxies, near the central black holes, can affect gas on the large scale - by stopping catastrophic cooling of the atmospheres of clusters of galaxies, and by gradually making cluster atmospheres more magnetic over cosmic time. It is widely believed that a feedback process, in which gas in clusters is reheated by the ejection of very hot, fast, gas from the regions near black holes is involved, at least in one heating mode. Our calculations have identified the population of sources responsible for this heating, and now want to understand how the process works for these objects.The fifth project involves the maintenance and improvement of codes used to work with catalogues of astronomical objects. These codes are essential when dealing with modern astronomical data, and are used world-wide, so are of great importance to many astronomers, but require development to deal with the increasing size and complexity of astronomical data. Some of the codes have even found their way into public products like the Microsoft World-Wide Telescope, and others are finding creative uses beyond astronomy.The final project is theoretical, and investigates the nature of the gas/dust disks around young stars in which planets form. As young pieces of planets collide and assemble into larger planets they can also destroy one another. Some of the dusty disks we see around young stars may show evidence of this destructive side of planet formation. The purpose of the high-performance computer calculations to be done in this project is to interpret the extreme examples of dusty disks to see if they are changing because of giant impacts between young planets. The results from the calculations will be compared with continuing observations of changing disk emission.

这项建议是为了资助布里斯托大学威尔斯物理实验室的研究人员研究天体物理学和宇宙学中的重要问题。过去几年来，许多宇宙学都是基于对星系团的研究，第一个项目是通过对星系团质量进行可靠的测量来确保星系团的有用性。这涉及到使用几种方法对来自X射线调查的集群样本进行严格的统计调查。星系团的质量范围很广，在宇宙年龄的一半以上都可以看到，所以我们还必须考虑星系团如何随时间变化。X射线来自星系团所拥有的热气大气层--尽管密度很低，但这些大气层占了正常物质的大部分质量，并且有其他可检测的影响，例如对微波背景辐射的影响。与非X射线质量测量技术的交叉检查将确保我们结果的可靠性。在较小的尺度上，我们知道单个星系也会随时间变化，但目前对这些变化如何依赖于星系质量和环境的了解甚少：例如，不同质量的星系以不同的速率变化。这些过程是如何相互作用和相互对抗以建立我们今天看到的星系群的尚不清楚，但我们积累的多波段光学数据允许测试星系如何变化，以及如何在低红移宇宙中推动星星的形成。在更高的红移，我们将寻找原星系团，其中包含最快的演变星系，以了解星系如何在早期的大质量结构的增长。基本上所有的大质量星系都包含大质量黑洞，或附近，他们的中心，和第三个项目将调查如何这样的黑洞能够创造强烈的中央辐射源，并将利用来自这些系统内部的X射线的亮度和光谱的变化来研究黑洞物理学和黑洞附近的气体。第四个项目着眼于单个星系中心靠近中心黑洞的微小区域，可以大规模地影响气体-通过阻止星系团大气的灾难性冷却，并通过在宇宙时间内逐渐使星系团大气更具磁性。人们普遍认为，至少在一种加热模式下，星系团中的气体被黑洞附近区域喷出的非常热、快速的气体重新加热，这是一个反馈过程。我们的计算已经确定了导致这种加热的源的数量，现在想了解这个过程是如何对这些物体起作用的。第五个项目涉及维护和改进用于天文物体目录的代码。这些代码在处理现代天文数据时是必不可少的，并且在世界范围内使用，因此对许多天文学家来说非常重要，但需要开发以处理越来越大和复杂的天文数据。其中一些代码甚至已经进入了微软全球望远镜（Microsoft World-Wide Telescope）等公共产品，还有一些代码正在天文学之外寻找创造性的用途。最后一个项目是理论性的，研究行星形成时年轻恒星周围的气体/尘埃盘的性质。当年轻的行星碎片碰撞并聚集成更大的行星时，它们也会相互毁灭。我们在年轻恒星周围看到的一些尘埃盘可能显示了行星形成过程中这种破坏性的一面。在这个项目中，高性能计算机计算的目的是解释尘埃盘的极端例子，看看它们是否因为年轻行星之间的巨大撞击而发生变化。计算的结果将与不断变化的圆盘发射的连续观测结果进行比较。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Evidence of a Clear Atmosphere for WASP-62b: The Only Known Transiting Gas Giant in the JWST Continuous Viewing Zone

DOI：
10.3847/2041-8213/abd18e
发表时间：
2020-11
期刊：
The Astrophysical Journal Letters
影响因子：
0
作者：
M. Alam;M. López-Morales;R. MacDonald;N. Nikolov;J. Kirk;J. Goyal;D. Sing;H. Wakeford;A. Rathcke;D. Deming;J. Sanz-Forcada;N. Lewis;J. Barstow;T. Mikal-Evans;L. Buchhave
通讯作者：
M. Alam;M. López-Morales;R. MacDonald;N. Nikolov;J. Kirk;J. Goyal;D. Sing;H. Wakeford;A. Rathcke;D. Deming;J. Sanz-Forcada;N. Lewis;J. Barstow;T. Mikal-Evans;L. Buchhave

The rise and fall of the UV upturn: z = 0.3, 0.55, and 0.7

UV 上升和下降：z = 0.3、0.55 和 0.7