Experimental radio cosmology at Oxford

在过去的15年里，由于对宇宙微波背景（CMB）波动的探测，我们对宇宙的理解发生了变化。这些波动是由原始宇宙流体密度的微小变化造成的，当时宇宙的年龄只有一秒的一小部分。这些被吹到天文学大小的宇宙的一个极其迅速的膨胀，持续了一分钟的几分之一秒;天文学家称之为“通货膨胀”的现象。已经建造了大量的仪器，通过测量这些各向异性的大小作为角度尺度的函数（它们的“功率谱”）来表征它们的空间分布。这些测量非常重要，因为它们告诉我们很多关于宇宙演化的信息，而且各向异性包含了导致宇宙目前结构的代码。牛津大学实验宇宙学小组的成员在宇宙学仪器如CAT、VSA和CBI方面发挥了主导作用。这些仪器和其他仪器，最著名的是美国宇航局的空间望远镜WMAP，揭示了令人难以置信的大量准确信息，例如宇宙具有平坦的几何形状，它的年龄是137亿年，宇宙中94%的物质不是我们所知道的物质，而是一种称为“暗物质”的新物质形式和一种更神秘的暗能量形式的组合。这就是故事的结局吗？相反，我们在过去15年中获得的知识促使我们寻求物理学和天文学中更基本问题的答案。暗物质是一个谜，因为我们不能直接探测到它，但我们至少可以清楚地观察到它的引力影响。然而，暗能量要奇怪得多，因为它导致宇宙的膨胀加速而不是减速。这真的是真的吗？或者有一种替代解释可以调和我们所有的观察结果？我们能否明确地证实暴胀确实发生了，如果是的话，在什么能量尺度上？这些都是下一代宇宙学仪器的挑战，这STFC赠款将使牛津大学作出重大贡献，这些令人兴奋的发展。我们的工作将以几种方式为下一个宇宙学的发展提供信息。我们参与了新的国家和国际宇宙学项目，这些项目的目标是比有史以来建造的任何仪器灵敏10倍。这些仪器将能够探测到极其微弱的信号，例如CMB偏振，它包含的信息与CMB各向异性一样多，从而使我们能够建立宇宙演化的完整图像。我们的团队包括天文学家，他们是仪器设计和建造以及观测和数据分析方面的专家。我们还建立了自己的小型仪器，以研究影响总体情况的具体影响，最后我们开发了支持上述活动的技术和天体物理学基础研究。我们在本申请中要求的支持福尔斯直接属于这些类别。我们请求支持博士后研究科学家分析天文数据，这些数据将来自我们正在努力建造的仪器。我们还要求努力帮助我们开发建造这些仪器所需的最先进的技术，最后，我们要求提供硬件，使我们能够在实验室开发和测试这项技术。这是一个令人兴奋的计划，将理论，天文观测和实验物理学联系起来，利用年轻科学家的巨大潜力来帮助我们了解我们周围的世界。

Our understanding of the universe has been transformed over the past 15 years as a result of the detection of the fluctuations in the Cosmic Microwave Background (CMB). These fluctuations result from tiny variations in the density of the primordial cosmic fluid when the universe was a tiny fraction of a second old. These were blown up to astronomical size by an extremely rapid expansion of the universe which lasted a minute fraction of a second; a phenomenon that astronomers call 'inflation'. A large number of instruments have been built to characterize the spatial distribution of these anisotropies by measuring their magnitude as a function of angular scale (their `power spectrum'). These measurements are very important because they tell us a lot about the evolution of the universe and because the anisotropies contain the code the led to the present structure in the universe. Members of the Experimental Cosmology group at Oxford have taken a leading role in cosmology instruments such as CAT, VSA and CBI. These instruments, and others, most notably the NASA space telescope WMAP, have revealed an incredible amount of accurate information, such as that the universe has a flat geometry, its age is 13.7 billion years and that 94% of the substance in the universe is not matter as we know it, but is a combination of a new form of matter called 'dark matter', and an even more mysterious form of dark energy. Is this then the end of the story then? On the contrary, the knowledge we have gained in the last 15 years induces us to seek answers to even more fundamental questions in physics and astronomy. Dark matter is a puzzle since we cannot detect it directly, but we can at least observe its gravitational impact clearly. Dark energy however is a lot more bizarre since it causes the expansion of the universe to accelerate rather than to slow down. Is this really true or is there an alternative explanation that reconciles all our observations? Can we confirm categorically that inflation really occurred and if so at what energy scale? These are the challenges of the next generation of cosmology instruments and this STFC grant will allow Oxford to make major contributions to these exciting developments. Our work will feed into the next cosmology developments in several ways. We take part in new national and international cosmology projects that are aiming to be 10 times more sensitive than any instrument ever built. These instruments will be able to detect extremely weak signals such as the CMB polarization that hold as much information as the CMB anisotropies, thereby allowing us to build a complete picture of the evolution of the universe. Our team includes astronomers who are experts in instrument design and construction and also in observation and data analysis. We also build our own small-scale instrument to investigate specific effects that feed into the general picture, and finally we develop the basic research in technology and astrophysics that supports the above mentioned activities. The support that we have requested in this application falls directly into these categories. We requested support for post-doctoral research scientists to analyse the astronomical data that will stream from instruments that we are working hard to build. We are also asking for effort to help us develop the state of the art technology that is required for building these instruments and finally we are asking for the hardware that will allow us develop and test this technology in our laboratories. It is an exciting programme that links theory, astronomical observation and experimental physics using the tremendous potential of bright young scientist to help us understand the world around us.