Astrophysics at the University of Birmingham

我们关于宇宙的大部分知识都来自科学家所说的“电磁辐射”--从无线电波到红外辐射和光，再到X射线和伽马射线。这在2015年9月14日发生了巨大的变化，当时我们第一次直接探测到时空中的涟漪，称为引力波。两个黑洞碰撞产生的第一个引力波信号（GW 150914）的观测揭开了天文学的新篇章。我们已经发现了双黑洞，并了解到在宇宙中每15分钟就有两个恒星质量的黑洞相撞。事实上，自2015年9月以来，我们已经观察到五次此类碰撞。2017年8月17日，我们观测到GW 170817，这是双中子星星的首次合并。在两颗中子星碰撞后产生的电磁辐射随后在整个电磁波谱中被检测到，从伽马射线到无线电波，这可能是天文学历史上对单个物体最密集的观测活动。第一次多信使观测表明，双中子星星合并是至少一些短硬伽马射线爆发的引擎，也是宇宙中产生重元素（如金）的重要场所。伯明翰小组在开发引力波仪器（Advanced LIGO）方面发挥了关键作用，这些仪器使这些发现，数据分析，源属性的表征以及GW 170817的后续观测活动成为可能。在未来的几年里，我们预计每周都能观测到引力波信号，甚至可能每天都能观测到。我们正准备利用这些来自黑洞和中子星合并的信号，更多地了解这些物体、恒星、物质在极端条件下的演化，并测试我们对引力本身的理解。我们还在开发先进技术，这是今后改进引力波观测站所必需的，以便能够观测和研究更多和弱得多的信号，更传统的仪器探测遥远宇宙的能力以及大型计算机模拟星系中心大质量黑洞影响的能力继续提高。我们将这些发展结合在一起，以推进我们对宇宙结构-大质量黑洞，星系和星系团-如何在宇宙时间中形成和演变的理解。天体物理学中的一个热门话题是努力理解神秘的“暗能量”，它为宇宙的加速膨胀提供动力。我们计划利用星系团作为宇宙最大尺度上的结构和膨胀历史的探测器，以推进我们对暗能量本质的理解。

Most of our knowledge about the Universe at large has been derived from what scientists refer to as "electromagnetic radiation" - ranging from radio waves through infrared radiation and light, to X-rays and gamma rays. This has changed dramatically on September 14, 2015 when we directly detected for the first time ripples in space-time known as gravitational waves. The observational of the first gravitational-wave signal (GW150914) generated by the collision of two black holes has opened a new chapter in astronomy. We have discovered binary black holes, and learnt that every 15 minutes somewhere in the Universe two heavy stellar-mass black holes collide. In fact, since September 2015 we have observed five more collisions of this kind. On August 17, 2017 we observed GW170817, the first merger of a binary neutron star. Electro-magnetic radiation generated in the aftermath of the collision of the two neutron stars was then detected across the entire electromagnetic spectrum, from gamma-rays to radio waves, in possibly the most intense observational campaign of a single object in the history of astronomy. This first multi-messenger observation has demonstrated that double neutron star mergers are the engine powering at least some short-hard gamma ray bursts, and an important site for production of heavy elements, such as gold, in the Universe. The Birmingham group has played a key role in the development of the gravitational-wave instruments (Advanced LIGO) that enabled these discoveries, the analysis of the data, the characterisation of the properties of the sources, and the follow-up observational campaign of GW170817. In the coming years we expect to be able to observe a gravitational-wave signal every week, or possibly every day. We are preparing to use these signals from merging black holes and neutron stars to learn more about the evolution of these objects, stars, matter in extreme conditions, and to test our understanding of gravity itself. We are also developing the advanced technology which will be required to make future improvements to gravitational-wave observatories, so that more and much weaker signals can be observed and studied.The capabilities of more conventional instruments to probe the distant Universe, and the capacity of large computers to simulate the influence of massive black holes at the centre of galaxies, continue to improve. We are bringing these developments together to advance our understanding of how structure in the universe - massive black holes, galaxies and clusters - form and evolve through cosmic time. A hot topic in astrophysics is the effort to understand the mysterious "dark energy" which powers the accelerating expansion of the Universe. We plan to use clusters of galaxies as probes of the structure and expansion history of the Universe on the largest scales, to advance our understanding of the nature of dark energy