Research in Astrophysics at The University of Bristol

这项提案是为了给布里斯托尔大学的天体物理学研究人员拨款。最近的许多宇宙学都是以对星系团的研究为基础的。第一个项目将对星团质量和其他参数进行可靠的测量。这包括对从x射线天空调查中提取的星团样本进行严格的统计调查——星团中的热气在x射线中发光。这些星团的质量范围很广，出现的时间超过了宇宙年龄的一半，所以我们要考虑它们随时间的演变。现今星团中的大质量星系拥有非常古老的恒星群。它们在大爆炸后的最初几十亿年里就完成了恒星的形成，这与大多数星系团外的星系不同。了解它们形成的细节对了解它们的性质至关重要。我们的第二个项目将识别和研究原始星团（今天星团的祖先）中的星系，当它们形成恒星时，建立星团及其星系相互关联演化的图像。第三个项目探索物质落入黑洞的物理原理。它将决定x射线观测如何可靠地测量黑洞质量、自旋速率和黑洞附近环境的几何形状。星系和它们中心的黑洞一起成长，所以对黑洞质量和自旋速率的可靠测量可以检验星系演化的模型。观察超大质量黑洞的近距离环境本身就很有趣，也是下一代x射线卫星（如欧空局的雅典娜天文台）的关键目标。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如何在大范围内影响气体——通过停止星系团大气的冷却，以及随着时间的推移使大气更具磁性。至少在一种加热模式下，一个反馈过程涉及到从黑洞附近区域喷出的非常热的、快速的气体来重新加热星系团气体。确定了这种加热的来源之后，我们现在想要了解这个过程是如何工作的。第五个项目涉及维护和改进TOPCAT软件，这是一种世界范围内使用的目录和数据操作工具，对许多天文学家在与越来越大和越来越复杂的数据集进行交互时非常重要，现在它正在发现远远超出天文学的创造性用途。该项目还将为关键的国际虚拟天文台框架作出贡献，该框架使TOPCAT和其他软件能够远程访问数据并实现它们之间的互操作性。第六个项目将使用手持HST和有保证的JWST对一颗凌日巨大系外行星的观测，通过测量其大气传输和发射，以前所未有的细节来表征其化学组成、动力学和演化。我们将利用这些观测结果为JWST开发新的数据分析管道，以生成单个系外行星大气的最完整数据集。另外两个项目从理论角度探索系外行星。七号计划调查年轻恒星周围形成行星的气体/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，它们可以相互毁灭。年轻恒星周围的一些圆盘可能显示出行星形成过程中破坏性的一面。我们将通过计算机计算来解释尘盘的极端例子，看看它们是否通过年轻行星之间的巨大撞击而进化。最后一个项目是对其他恒星周围行星大气中极地涡旋的理论研究，以及它们如何影响它们的可居住性。当与JWST观测相结合时，它将得出TRAPPIST-1e大气的详细模型，TRAPPIST-1e是一颗地球大小的系外行星，在其恒星的宜居带轨道上运行。

This proposal is for a grant to researchers in astrophysics at the University of Bristol.Much recent cosmology has been based on investigations of galaxy clusters. The first project will make reliable measurements of cluster masses and other parameters. This involves statistically rigorous investigations of cluster samples drawn from X-ray sky surveys - the hot gas in the clusters shines in X-rays. The clusters span a wide mass range and are seen over half the age of the Universe, so we take into account their evolution over time.Massive galaxies within current-day clusters have very old stellar populations. They finished forming their stars in the first few billion years after the big bang, unlike most galaxies outside clusters. Understanding details of their formation is crucial to understanding their nature. Our second project will identify and study galaxies in proto-clusters (progenitors of today's clusters) as they form their stars, building a picture of the inter-related evolution of clusters and their galaxies.A third project explores the physics of matter falling into black holes. It will determine how X-ray observations can reliably measure the black hole mass, spin rate, and geometry of the environment close to the black hole. Galaxies and their central black holes grow together, so reliable measurements of black hole mass and spin rates can test models of galaxy evolution. Observing the close environment of super-massive black holes is both intrinsically interesting, and is a key goal for the next generation of X-ray satellites such as the ESA's Athena observatory.A fourth project looks at how tiny regions in the centres of individual galaxies, near central black holes, affect gas on the large scale - by stopping cooling of the atmospheres of galaxy clusters, and by making the atmospheres more magnetic over time. A feedback process, in which cluster gas is reheated by the ejection of very hot, fast, gas from the regions near black holes is involved, at least in one heating mode. Having identified the sources responsible for this heating, we now want to understand how the process works.The fifth project involves maintenance and improvement of the TOPCAT software, a catalogue and data manipulation tool used world-wide and of great importance to many astronomers in their interactions with data sets of increasing size and complexity and which is now finding creative uses well beyond astronomy. The project will also contribute to the critical international Virtual Observatory framework that enables remote data access for TOPCAT and other software and interoperability between them.A sixth project will use in-hand HST and guaranteed JWST observations of a transiting giant exoplanet to characterise the chemical makeup, dynamics, and evolution through measurements of its atmospheric transmission and emission in unprecedented detail. We will use these observations to develop new data analysis pipelines for JWST to produce the most complete dataset for a single exoplanet atmosphere. Two further projects explore exoplanets from a theoretical perspective. Project seven 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 destroy one another. Some disks around young stars may show evidence of this destructive side of planet formation. We will carry out computer calculations to interpret extreme examples of dusty disks to see if they evolve through giant impacts between young planets.The final project is a theoretical study into polar vortices in the atmospheres of planets around other stars and how they may affect their habitability. When combined with JWST observations, it will result in a detailed model of the atmosphere of TRAPPIST-1e, an Earth-sized exoplanet orbiting in its star's habitable zone.