Astrophysics at Oxford 2016-2019

牛津大学的天体物理研究是由具有广泛兴趣的研究人员进行的，范围从行星到宇宙。我们的活动是普遍的，在这个词的每一个意义上。我们积极研究现代物理学中许多最激动人心的问题。在熟悉的行星现象尺度上，我们试图了解遥远世界的海洋、大气和气候模式是如何表现的。我们正在研究其他太阳系是如何形成和演化的，以及为什么它们看起来与我们自己的太阳系如此不同。恒星是我们这门学科的历史主题。我们正在研究双星合并的过程，以及当其中一颗恒星是黑洞时，当其中一颗恒星是黑洞时，如何通过吸积X射线发射气体来形成圆盘和大喷流。在与银河系相关的更大尺度上，我们非常详细地研究单个恒星的组合运动，利用结果来理解银河系如何保持其结构，以及巨大的不可见暗物质如何通过可见发光物质的运动间接揭示其存在。星系中的气体吸积到中央黑洞上，其后果从类星体和活动星系核的壮观后果到我们银河系的微光。牛津大学的研究人员研究银河中心，以了解其详细的物理学，并探测遥远星系中的气体分子，以揭示隐藏在各自中心区域的黑洞的性质。虽然形成恒星的气体最初是非常冷的，但星系中的大部分气体都非常热和稀薄。这些完全电离的空间等离子体与磁场强烈耦合，表现出非常不寻常和复杂的行为，其中许多方面根本不被理解。牛津大学的研究人员试图了解粒子是如何在等离子体冲击波中加速产生巨大能量的，并计算当质子和电子成为吸积流的一部分时，它们是否相互作用并相互加热。这些问题对于我们理解动力学理论的基本过程是至关重要的，其意义远远超出了天体物理学的界限。星系的形成和演化受其环境的影响，而环境又受星系本身的存在的极大影响。要在整个宇宙时间中解开这一细节是一项艰巨的任务，需要获取和分析大量的观测数据。牛津天体物理学维持着一个庞大的、活跃的研究小组，从星系形成的最高红移到现在的宇宙时代，在它的所有范围内都在研究这个宏大的问题。关于恒星形成的速度，星系形态本身如何随时间变化，邻居的存在是否会导致自旋排列，中央黑洞如何发展等问题，都在牛津大学进行研究。这涉及利用现有设施以及规划设计和实施与重大国际合作有关的主要文书。其中最大的尺度与宇宙微波背景CMB有关。从我们的银河系去除前景污染(包括极化和非极化的)的过程极其困难，但却是必不可少的，这一过程是由开发C-Bass仪器的牛津团队领导的。牛津大学的研究人员正在开发技术，从非常敏感的数据中诱使出宇宙的深刻秘密。最初产生星系及其更大规模星系团的微小波动是什么？可以对基本粒子的质量或偏离经典广义相对论施加什么限制？通过将来自普朗克等CMB仪器的信息与其他与星系团有关的数据集相结合，正在开发强大的新工具。

Astrophysical research at Oxford University is carried out by investigators with widespread interests, spanning scales from planetary to cosmic. Our activities are universal, in every sense of this word. We are actively engaged with many of the most exciting questions of modern physics. On the familiar scale of planetary phenomena, we seek to understand how the oceans, atmospheres and climate patterns of distant worlds behave. We are investigating how other solar systems form and evolve, and why they seem to be so different from our own.Stars are the historical staple of our discipline. We are investigating the processes by which binary stars merge, and how discs and great jets form from accreting, X-ray emitting gas when one of the stars is a black hole. On larger scales associated with the Milky Way Galaxy, we study the combined motions of individual stars in great detail, using the results to understand how the Galaxy maintains its structure, and how a great halo of invisible dark matter reveals its presence indirectly through the motions of visible luminous matter. Gas in galaxies accretes onto central black holes, with consequences that range from spectacular in the case of quasars and active galactic nuclei, to barely a blip in the case of our own Galaxy. Oxford researchers study the Galactic Centre to understand its detailed physics, and probe gas molecules in distant galaxies to reveal the properties of the black holes harboured in their own central regions. While the gas that forms stars is initially very cool, much of the gas in galaxies is very hot and dilute. These completely ionised space plasmas, which couple strongly to magnetic fields, exhibit very unusual and complex behaviour, many aspects of which are not at all understood. Oxford researchers seek to understand how particles are accelerated to enormous energies in plasma shock waves, and in calculating whether protons and electrons interact and mutually heat one another when they are part of an accretion flow. These are problems that are critical to our understanding of fundamental processes of kinetic theory, whose significance extends well beyond the boundary of astrophysics. The formation and evolution of galaxies is influenced by their environment, which is in turn greatly impacted by the presence of the galaxies themselves. To unravel the details of this throughout cosmic time is an enormous task, requiring the acquisition and analysis of vast amounts of observational data. Oxford Astrophysics maintains a large, active group of researchers pursuing this grand problem in all of its scope, from the highest redshifts at which galaxies form, down through present cosmic times. Questions pertaining to the rate of star formation, to how galaxy morphology itself may change with time, to whether the presence of neighbours causes spin alignment, to how the central black hole develops, are all being investigated at Oxford. This involves the use of current facilities as well as planning the design and implementation of key instruments to be associated with major international collaborations. The largest scales of all are associated with the CMB, the cosmic microwave background. The exquisitely difficult but essential process of excising the foreground contamination from our own Galaxy (both polarised and unpolarised) is led by the Oxford team developing the C-BASS instrument. Oxford researchers are developing techniques to coax profound secrets of the universe from very sensitive data. What were the initial tiny fluctuations that gave rise to galaxies and their larger scale clusters? What constraints can be placed on the masses of elementary particles or on deviations from classical general relativity? By combining information from CMB instruments like Planck with other data sets related to galaxy clustering, powerful new tools are being developed.