Survey Cosmology and Astrophysics

这项滚动拨款是为了支持朴茨茅斯大学宇宙学和引力研究所（ICG）的宇宙学家和天体物理学家。ICG于2002年通过该大学的一项战略投资成立，现在拥有多达50名研究人员，使其成为英国最大的星系外团体之一。由于技术和理论的新进步，宇宙学和天体物理学正在经历一个发现的黄金时代。然而，在建立一个更完整的宇宙模型之前，我们仍然面临着两个根本性的挑战：1)构成宇宙96%的“暗物质”和“暗能量”的特性是什么？ 2)构成宇宙的“积木”——星系是如何形成和演化的？这笔拨款将通过使用新的、大规模的天空调查来解决这两个基本问题。例如，我们将在智利的布兰科4米望远镜上安装一台新的5.2亿像素相机，对南部天空进行数字成像。这项调查——被称为暗能量调查（DES）——将探测到3亿个星系，从而使我们能够高精度地测量星系群，并探测到由于前景暗物质导致的遥远星系的弱引力透镜效应。DES还将发现数千颗遥远的超新星（爆炸的恒星），它们将决定宇宙在其生命周期的70%以上的膨胀。我们是唯一一个参与新的斯隆数字巡天III （SDSS-III）重子振荡光谱巡天（BOSS）的英国天文小组，该巡天将测量超过150万个星系的红移（以及距离），超过宇宙年龄的一半。BOSS项目始于2009年，我们将利用这些数据来研究大质量星系的演化，特别是与ICG独家生产的最新星系理论模型进行比较，了解宿主星系对超新星爆炸的影响，并利用重子声学振荡高精度地确定宇宙的几何形状。除了新的光学巡天，我们还计划利用正在建造的下一代射电望远镜的力量。其中第一个是LOFAR，它的基站遍布欧洲，形成了一个面积超过600公里的有效射电望远镜。我们将利用LOFAR，结合SDSS的新数据，研究超大质量黑洞对椭圆星系演化的影响。从这些黑洞流出的能量被认为是减缓这些星系增长的一种方式，使它们今天“红而死”。此外，LOFAR的数据可以用来通过“综合萨克斯-沃尔夫”效应来理解暗能量，这种效应对宇宙中结构的增长速度特别敏感，因此对宇宙尺度上的引力强度也特别敏感。因此，LOFAR将成为检验爱因斯坦广义相对论的有力工具，广义相对论是宇宙学的基础。加在一起，我们期望测量宇宙年龄70%以上的暗能量密度。这将告诉我们它是否只是一个常数，就像爱因斯坦最初提出的那样，或者是更奇特的东西，如Quintessence，“幻影能量”或额外维度！这些数据还将揭示暗物质的特性，我们可以通过引力“看到”暗物质，但它不像普通物质那样发光。我们还将更全面地了解大质量星系在整个宇宙时间内的特征。这将告诉我们冷暗物质理论是否对星系的形成和演化提供了充分的描述。除了研究之外，ICG的工作人员还致力于公众宣传，并在媒体和当地社区中参与了一些明显的活动。例如，我们的员工参观了许多当地的学校，讨论他们的职业生涯，他们的研究（如银河动物园），并表达了做研究的乐趣。

This rolling grant is to support cosmologists and astrophysicists at the Institute of Cosmology and Gravitation (ICG) at the University of Portsmouth. The ICG was formed in 2002 through a strategic investment from the university, and now hosts up to 50 researchers making it one of the largest extragalactic groups in the UK. Cosmology and astrophysics are experiencing a golden age of discovery driven by new advances in technology and theory. However, we still face two fundamental challenges before a more complete model of the Universe can be achieved: i) What are the properties of the 'dark matter' and 'dark energy' that make up 96% of the Universe, and ii) how do galaxies - the 'building blocks' of the Universe - form and evolve? This grant will address both these fundamental problems through the use of new, massive surveys of the sky. For example, we will use a new 520-megapixel camera on the Blanco 4-meter telescope in Chile to digitally image the southern sky. This survey - known as the Dark Energy Survey (DES) - will detect 300 million galaxies thus allowing us to measure the clustering of galaxies to high precision and detect the weak gravitational lensing of distant galaxies due to the foreground dark matter. DES will also discover thousands of distant supernovae (exploding stars) which will determine the expansion of the Universe over 70% of its lifetime. We are the only UK astronomy group involved in the new Sloan Digital Sky Survey III (SDSS-III) Baryon Oscillation Spectroscopic Survey (BOSS) which will measure the redshift (and thus distance) to over 1.5 million galaxies over half the age of the Universe. BOSS started in 2009 and we will use these data to study the evolution of massive galaxies, especially when compared to the latest theoretical models of galaxies produced exclusively at the ICG, understand the effect of host galaxies on supernova explosions and determine the geometry of the Universe to high precision using the Baryon Acoustic Oscillations. In addition to new optical surveys, we plan to harness the power of the next generation of radio telescopes that are just being built. The first of these is LOFAR, which has base stations spread across Europe forming an effective radio telescope over 600 kilometres in size. We will use LOFAR, in conjunction with new data from the SDSS, to study the effects of supermassive black holes on the evolution of elliptical galaxies. The energetic outflows from these black holes has been proposed as a way of slowing down the growth of such galaxies, making them 'red and dead' today. Also, the LOFAR data can be used to understand dark energy through the 'Integrated Sachs-Wolfe' effect, which is particularly sensitive to the rate of growth of structures in the Universe and thus the strength of gravity on cosmological scales. Therefore, LOFAR will be a powerful tool for testing Einstein's Theory of General Relativity which is fundamental to cosmology. Taken together, we expect to measure the density of dark energy over 70% the age of the Universe. This will tell us if it is just a constant, as first proposed by Einstein, or something more exotic like Quintessence, 'phantom energy' or extra dimensions! This data will also shed light on the properties of dark matter, which we can 'see' via gravity but does not shine like normal matter. We will also obtain a fuller understanding of the characteristics of massive galaxies throughout cosmic time. This will tell us whether the cold dark matter theory provides an adequate description of the formation and evolution of galaxies. In addition to research, the ICG staff are committed to public outreach and have been engaged in a number of visible activities in the media and local community. For example, our staff have visited many local schools to discuss their careers, their research (e.g. Galaxy Zoo), and express the fun of doing research.