Imperial College Astrophysics: Consolidated Grant 2012-2014

帝国理工学院天体物理学利用世界上和太空中最先进的天文仪器的数据来理解当今一些最重要的科学问题：-宇宙是由什么组成的，它是如何演变的？- 星系、恒星和行星是如何形成和演化的？为了解决这些问题，我们必须用复杂的模型来研究宇宙的整体结构及其组成部分，在最大的尺度上，我们将使用宇宙微波背景（CMB），即大爆炸后40万年最后一次与其他物质相互作用的光子。CMB为我们提供了早期宇宙的快照，当时它是热的，致密的和简单的。结合我们对物理定律的理解，我们的观测为我们提供了关于宇宙最大尺度的丰富信息：我们可以检验所谓的哥白尼原理，即我们对宇宙各向同性的假设。我们还可以观察到宇宙膨胀的影响，这是一个加速膨胀的早期阶段，被认为是宇宙中物质分布的原因。类似地，对遥远超新星的观测等数据将使我们能够绘制出离地球稍近的宇宙膨胀图，大约是CMB探测到的表面的一半。将这些数据与其他望远镜和实验（如欧洲核子研究中心的大型强子对撞机）的信息结合起来，我们可以探测物质的基本组成，并确定暗物质，它在宇宙中的物质数量大约是组成我们的原子的五倍。有了这些粒子物理学和宇宙学模型，我们拥有必要的背景知识，可以通过地面和空间望远镜的大型观测来了解星系及其内部恒星的演化。赫歇尔空间天文台是最灵敏的仪器，能够观测到宇宙中大约50%的光子，这些光子是由大多数星系的恒星之间的尘埃发出的（尘埃本身是由这些星系中的早期恒星产生的）。通过了解这种辐射的过程，我们可以建立一个像我们银河系这样的星系集合的图像，对天空的大规模调查也给了我们一个寻找极端物体的潜在窗口：最遥远的，或最大的，或最冷的物体，潜伏在我们的数据的边缘。然而，找到它们不仅需要大量的数据，还需要强大的统计技术来筛选它们。这些技术已经发现了最遥远的类星体，我们准备在新的数据集中发现更多不寻常的物体。

Imperial College Astrophysics uses data from the most sophisticated astronomical instruments in the world and in space to understand some of the most important scientific questions of the day: - What is the universe made of and how does it evolve? - How do galaxies, stars and planets form and evolve?To address these questions, we must confront the data with sophisticated models for the overall structure of the Universe as well as its constituents.On the very largest scales, we will be using the Cosmic Microwave Background (CMB), photons which last interacted with other matter only 400,000 years after the big bang. The CMB gives us a snapshot of the early Universe when it was hot, dense and simple. Combined with our understanding of the physical laws, our observations give us a wealth of information about the Universe on its largest scales: we can test the so-called Copernican Principle, our assumption of the isotropy of the Universe. We can also observe the effects of cosmological inflation, an early period of accelerated expansion thought to be responsible for the distribution of matter in the Universe. Similarly, data such as observations of distant supernovae will allow us to map the expansion of the Universe slightly closer to home, roughly half way to the surface probed by the CMB.Combining these data with information from other telescopes and experiments such as the LHC at CERN, we can probe the fundamental constituents of matter, and identify the dark matter which accounts for roughly fives times more matter in the Universe than the atoms we are made of.Armed with these models of particle physics and cosmology, we have the necessary background to understand the evolution of galaxies and the stars within them, probed using large surveys with ground and space-based telescopes. The Herschel Space Observatory is the most sensitive instrument capable of observing the roughly 50% of all photons in the Universe that are emitted by the dust that lurks between the stars of most galaxies (dust that itself is produced by earlier generations of stars in those same galaxies). By understanding the processes responsible for this radiation we can build a picture of the assembly of galaxies like our own Milky Way.Large surveys of the sky also give us a potential window for finding extreme objects: the most distant, or most massive, or coldest objects that lurk at the outskirts of our data. However, finding them requires not only lots of data, but also robust statistical techniques to sift through them. These techniques have already found the most distant quasar and we are poised to find yet more unusual objects in new datasets.