Astrophysics at the University of Birmingham

我们对整个宇宙的大部分知识都来自于科学家所说的“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日发生了戏剧性的变化，我们第一次直接探测到时空中的涟漪，即引力波。观测到由两个黑洞碰撞产生的第一个引力波信号（GW150914），开启了天文学的新篇章。我们已经发现了双黑洞，并且了解到在宇宙的某个地方每15分钟就有两个重恒星质量的黑洞相撞。事实上，自2015年9月以来，我们已经观测到五次这样的碰撞。2017年8月17日，我们观测到了GW170817，这是第一次双中子星的合并。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探测到，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强烈的观测活动。这一首次多信使观测表明，双中子星合并至少是一些短硬伽马射线爆发的引擎，也是宇宙中重元素（如金）产生的重要场所。伯明翰小组在引力波仪器（高级LIGO）的发展中发挥了关键作用，使这些发现成为可能，数据分析，源特性的特征，以及GW170817的后续观测活动。在未来的几年里，我们希望每周都能观测到引力波信号，或者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来更多地了解这些物体、恒星和物质在极端条件下的演化，并测试我们对引力本身的理解。我们还在开发先进的技术，这些技术将用于将来对引力波天文台进行改进，以便能够观察和研究更多更弱的信号。探测遥远宇宙的更传统仪器的能力，以及模拟星系中心大质量黑洞影响的大型计算机的能力，都在不断提高。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化的理解。天体物理学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探测器，在最大尺度上探索宇宙的结构和膨胀历史，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