Extragalactic Astrophysics and Cosmology at Imperial College London

伦敦帝国理工学院河外天体物理学和宇宙学

• 批准号: ST/G001901/1
• 负责人: Andrew Jaffe
• 金额: $ 175.73万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FG001901%2F1
• 关键词: Extragalactic; Astrophysics; Cosmology; Imperial; College

Our work in the Astrophysics Group at Imperial College London, in the broadest terms, is aimed at improving our understanding of the evolution of the Universe. The basic framework is the Big Bang model, the picture that the Universe began in a hot violent explosion several billion years ago. As the Universe expands it cools, and under the force of gravity matter segregates and condenses to form galaxies composed of stars. Our current picture of the Universe has changed dramatically in recent decades, both observationally and theoretically. The most important observational improvement has been the development of telescopes that map the sky over the complete range of wavelengths, both shorter than visual - gamma-ray, X-ray, ultraviolet - and longer than visual - infrared, microwave, radio. Two surprising results have emerged from these observations. First, there must be much more matter, dark matter, in the Universe than we can see, to explain the strong gravitational pull of galaxies. Second, the expansion of the Universe is accelerating, which we can only understand if empty space (the vacuum, nothing) possesses energy, dark energy. The aim of our work at Imperial College London, then, is to undertake observations and theoretical studies to develop this picture of the evolution of the Universe in more detail. We can order our research by wavelength, starting with X-rays. The shorter the wavelength of light, the higher the energy of photons, so X-rays can be used to study the most energetic processes in galaxies, particularly the accretion of matter onto black holes, and we are using the XMM-Newton satellite to explore these extreme environments. There is a very massive black hole, over a million times the mass of the Sun, at the centre of most galaxies, and a recent discovery has been that the mass of the black hole is proportional to the mass of the galaxy in which it lies. Our work using the Chandra satellite is aimed at understanding why this is and the implications for how galaxies form. At near-infrared wavelengths we are taking advantage of a new generation of large detectors to make a deep map of the sky, and are using this survey to search for distant quasars. The expansion of the Universe stretches (redshifts) the light from far away sources, so the most distant sources are the most redshifted. Light from the furthest quasars, from the time when they were first forming, is stretched to the near-infrared. By discovering the first quasars we can analyse their light to tell us about the conditions at that time, when the Universe was only 5% of its present age. Although stars emit most of their light near optical wavelengths, an important development in the 1980s and 1990s was the discovery that much of this light is hidden by the smoke from burning stars ('dust' to astronomers). The light is absorbed by dust and re-emitted at far-infrared wavelengths. About half of all starlight emerges at far-infrared wavelengths, so we need to study galaxies at these wavelengths to make a complete census of where and when the stars we see today formed. To this end over the next few years we will be analysing far-infrared maps made with the Herschel satellite, due to be launched in 2008. Finally, at microwave wavelengths we can see the furthest back in time, to the point when the Universe was so hot that matter was in the form of a plasma. In effect the entire sky looks like the surface of the sun, but that light has been redshifted by a factor of 1000, and stretched to microwave wavelengths. Analysis of the subtle variations in temperature of the microwave sky can provide a measurement of the amount of dark matter and dark energy. The launch of the Planck satellite in 2008 will provide the most detailed maps yet of the microwave sky. We will analyse the structure in these maps to obtain the most accurate measure of these cosmological parameters.

我们在伦敦帝国理工学院天体物理学组的工作，从最广泛的角度来看，旨在提高我们对宇宙演化的理解。基本框架是大爆炸模型，宇宙在几十亿年前的一次热的剧烈爆炸中开始。随着宇宙的膨胀，它冷却了，在重力的作用下，物质分离并凝聚成由恒星组成的星系。近几十年来，我们目前对宇宙的看法在观测和理论上都发生了巨大的变化。最重要的观测改进是望远镜的发展，它可以在整个波长范围内绘制天空，既包括短于可见光的伽马射线，X射线，紫外线，也包括长于可见光的红外线，微波，无线电。从这些观察中出现了两个令人惊讶的结果。首先，宇宙中的物质，暗物质，一定比我们能看到的要多得多，才能解释星系的强大引力。其次，宇宙的膨胀正在加速，我们只能理解，如果空的空间（真空，什么都没有）拥有能量，暗能量。因此，我们在伦敦帝国理工学院工作的目的是进行观测和理论研究，以便更详细地发展这幅宇宙演化的图景。我们可以按照波长来排列我们的研究，从X射线开始。光的波长越短，光子的能量就越高，因此X射线可以用来研究星系中能量最大的过程，特别是物质在黑洞上的吸积，我们正在使用XMM-牛顿卫星来探索这些极端环境。在大多数星系的中心都有一个非常巨大的黑洞，质量超过太阳的一百万倍，最近的一项发现是，黑洞的质量与它所在星系的质量成正比。我们使用钱德拉卫星的工作旨在了解这是为什么以及星系如何形成的影响。在近红外波段，我们正在利用新一代大型探测器来绘制天空的深度图，并利用这一调查来寻找遥远的类星体。宇宙的膨胀会拉伸（红移）来自遥远光源的光，所以最远的光源是最红移的。来自最远的类星体的光，从它们最初形成的时候开始，被拉伸到近红外线。通过发现第一批类星体，我们可以分析它们的光，告诉我们当时的情况，当时宇宙只有现在年龄的5%。虽然恒星发出的大部分光接近光学波长，但在20世纪80年代和90年代的一个重要发展是发现这些光中的大部分被燃烧恒星的烟雾（天文学家称为“尘埃”）所隐藏。光线被尘埃吸收，并以远红外波长重新发射。大约一半的星光出现在远红外波长，所以我们需要研究这些波长的星系，以全面普查我们今天看到的恒星形成的时间和地点。为此，在今后几年中，我们将分析用定于2008年发射的赫歇尔卫星制作的远红外地图。最后，在微波波长下，我们可以看到最远的时间，当宇宙如此之热，物质以等离子体的形式存在时。实际上，整个天空看起来就像太阳的表面，但这些光已经被红移了1000倍，并被拉伸到微波波长。分析微波天空温度的微妙变化可以提供暗物质和暗能量的测量。2008年普朗克卫星的发射将提供迄今为止最详细的微波天空地图。我们将分析这些地图中的结构，以获得这些宇宙学参数的最准确测量。

项目成果

PRISM (Polarized Radiation Imaging and Spectroscopy Mission): an extended white paper

• DOI: 10.1088/1475-7516/2014/02/006
• 发表时间: 2013-10
• 期刊: Journal of Cosmology and Astroparticle Physics
• 影响因子: 6.4
• 作者: Prism Collaboration Philippe Andr'e;C. Baccigalupi;A. Banday;D. Barbosa;B. Barreiro;J. Bartlett;N. Bart

HERUS: The far-IR/submm spectral energy distributions of local ULIRGs and photometric atlas

• DOI: 10.1093/mnras/stx3227
• 发表时间: 2017-12
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: D. Clements;C. Pearson;C. Pearson;C. Pearson;D. Farrah;J. Greenslade;J. Bernard-Salas;E. González-Alfonso;J. Afonso;A. Efstathiou;D. Rigopoulou;D. Rigopoulou;V. Lebouteiller;V. Lebouteiller;P. Hurley;H. Spoon

Cosmic sculpture: a new way to visualise the cosmic microwave background

宇宙雕塑：一种可视化宇宙微波背景的新方法

• DOI: 10.1088/0143-0807/38/1/015601
• 发表时间: 2017
• 期刊: European Journal of Physics
• 影响因子: 0.7
• 作者: Clements D

MADmap: A MASSIVELY PARALLEL MAXIMUM LIKELIHOOD COSMIC MICROWAVE BACKGROUND MAP-MAKER

• DOI: 10.1088/0067-0049/187/1/212
• 发表时间: 2009-06
• 期刊: The Astrophysical Journal Supplement Series
• 作者: C. Cantalupo;J. Borrill;A. Jaffe;T. Kisner;R. Stompor

H-ATLAS: A Candidate High Redshift Cluster/Protocluster of Star-Forming Galaxies

• DOI: 10.1093/mnras/stw1224
• 发表时间: 2016-05
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: D. Clements;F. Braglia;G. Petitpas;J. Greenslade;A. Cooray;E. Valiante;G. Zotti;B. O’Halloran;J. Holdship;B. Morris;I. Pérez-Fournon;D. Herranz;D. Riechers;M. Baes;M. Bremer;N. Bourne;H. Dannerbauer;A. Dariush;L. Dunne;S. Eales;J. Fritz;J. González-Nuevo;R. Hopwood;E. Ibar;R. Ivison;L. Leeuw;S. Maddox;M. Michałowski;M. Negrello;A. Omont;I. Oteo;S. Serjeant;I. Valtchanov;J. Vieira;J. Wardlow;P. Werf