Unveiling the Hidden Universe - from the first galaxies to brown dwarves

天文学中最大的三个问题是：(1)恒星是如何形成的？星系是如何形成的？(3)宇宙是如何随时间变化的？用传统的光学望远镜很难回答这些问题。首先，我们现在知道恒星和星系的诞生在很大程度上被宇宙尘埃所掩盖，宇宙尘埃吸收了可见光，然后以远红外和亚毫米波波段辐射能量。其次，我们现在也知道宇宙是由暗物质和“暗能量”主导的，暗物质不以任何电磁波波段辐射，而“暗能量”是一种我们比暗物质更不了解的物质。在回答所有这些问题方面，英国天文学家处于一个非常有利的位置，可以取得实质性的进展。2007年在詹姆斯·克拉克·麦克斯韦望远镜上安装了SCUBA-2亚毫米相机，并于2008年发射了赫歇尔空间天文台，这是一台将彻底改变远红外和亚毫米天文学的望远镜，将使通过观察尘埃辐射来研究恒星和星系的早期生命成为可能。其他新设施将使间接推断暗物质和能量的性质成为可能，特别是从它的引力效应。我们提出一项旨在回答所有这些问题的研究计划。基于我们强大的亚毫米天文学传统（卡迪夫是英国赫歇尔空间天文台的主要中心）和恒星形成的计算机模拟，我们提出了许多理论和观测项目，以揭示恒星的早期生命，并发现它们最初形成的方式和原因。我们还提出了一个项目，旨在发现我们今天周围看到的椭圆星系是否是100亿年前充满宇宙的发光尘埃星系的后代。最后，我们提出了两个项目来尝试回答第三个问题。宇宙的演化关键取决于它的黑暗成分。首先，我们将开展一个项目来测量我们附近的暗星系的数量，暗星系中没有恒星，只有气体和暗物质。其次，我们将利用与赫歇尔同时发射的普朗克卫星的结果来研究遥远星系团的性质，这将使我们能够推断暗能量的性质。

Three of the biggest questions in astronomy are: (1) how do stars form? (2) How did galaxies form? (3) How has the Universe changed over time? It is hard to answer these questions with traditional optical telescopes. First, we now know that the birth of both stars and galaxies is largely hidden from view by cosmic dust, which absorbs the optical light and then reradiates the energy in the far-infrared and submillimetre wavebands. Second, we also know now that the Universe is dominated by dark matter, which does not radiate in any electromagnetic waveband, and 'dark energy', a substance we know even less about than dark matter. UK astronomers are in an excellent position to make substantial progress in answering all of these questions. The installation of the SCUBA-2 submillimetre camera on the James Clerk Maxwell Telescope in 2007 and the launch in 2008 of the Herschel Space Observatory, a telescope which will revolutionize far-infrared and submillimetre astronomy, will make it possible to study the early lives of stars and galaxies by observing the radiation from the dust. Other new facilities will make it possible to infer the properties of the dark matter and energy indirectly, in particular from its gravitational effects. We propose a research programme aimed at answering all of these questions. Building on our strong traditions of submillimetre astronomy (Cardiff is the main UK centre for the Herschel Space Observatory) and computer simulations of star formation, we propose a number of theoretical and observational projects to uncover the early lives of stars, and also to discover how and why they form in the first place. We also propose a project aimed at discovering whether the elliptical galaxies we see around us today are the descendants of the luminous dusty galaxies that filled the Universe ten billion years ago. Finally, we propose two projects to try to answer the third question. The evolution of the Universe depends critically on its dark component. First, we will carry out a project to measure the number of dark galaxies, ones in which contain no stars but only gas and dark matter, in our local neighbourhood. Second, we will use the results from the Planck satellite, which will be launched at the same time as Herschel, to study the properties of distant galaxy clusters, which will allow us to infer the properties of the dark energy.