Queen's University Belfast Astronomy Observation and Theory Consolidated Grant 2017-2020

超新星创造了我们在太阳系、银河系和整个可见宇宙中看到的重化学元素。虽然恒星经过数百万年或数十亿年的演化，但超新星爆炸只发生在几秒钟内，发光的残余物持续数年。我们的目标是了解这些爆炸是如何发生的，以及它们是如何在银河系中创造中子星、脉冲星和黑洞的。大质量恒星的核心在其核燃烧寿命结束时坍塌，释放的引力势能通过中微子与恒星密集的内部区域的相互作用驱动爆炸。最大质量的恒星如何爆炸，以及黑洞是否形成，都是不确定的，而且在已知的超新星群体中观察到的能量存在巨大的多样性。我们提出的工作将解决这些问题，并试图找到可能在宇宙中产生引力波的来源。最有可能的来源是合并的中子星或黑洞，预计最终会发现引力波。然后，问题将转向寻找消息来源。被用作宇宙尺度并导致诺贝尔奖获得者发现暗能量的热核超新星来自白矮星。但它们是如何爆炸的，以及它们的前身系统是什么，我们仍然不得而知。两颗合并白矮星的竞争模型，或者单个白矮星与正常恒星伴星的竞争模型仍然是可行的。最有可能的是，有几种方法可以炸毁一颗白矮星--一颗比太阳质量大、但与地球大小相同的恒星。凭借我们的理论计算机代码和世界领先的天文测量数据，我们处于有利地位，可以在这些领域取得进展。超新星中产生的元素形成了我们银河系的行星系统--铁、硅、氧、镁都是形成行星系统的关键。我们银河系中其他恒星(称为系外行星)周围的已知行星系统的多样性令人震惊。我们知道有数以千计的系外行星，其中有巨大的热木星，多个行星系统和超级地球，现在普遍存在。我们可以看到年轻恒星在生命的最初几百万年里，在它们的圆盘中形成了行星。在南半球(ALMA)建造的最新大型设施提供了关于原行星盘的壮观数据，我们在盘化学方面的工作旨在了解它们的起源。我们的工作将通过仔细提取从母星通过行星大气层的光来探测这些遥远星球的大气层。我们还可以测量恒星的年龄，以限制行星系统如何随时间演化，以及对有生命的行星可能存在的限制。这一领域的当务之急是找到另一颗类似地球的行星--合适的大小、年龄和与母星的距离，以支持大气层和液态水。这种搜索需要仔细考虑和测试提取我们期望的微小信号的方法，我们建议发展这一方法，着眼于未来探测地球孪生兄弟的奖赏。天体物理学的一个关键部分是把我们在地球上可以测量到的详细的物理学知识整合到我们在遥远的宇宙中只能看到的东西(通过电磁辐射)。这将通过模型原子的计算机计算来完成。这些代码计算电子在原子中是如何激发的，并确保天体物理代码识别导致我们在超新星、超大质量黑洞、星系光谱和恒星中看到的谱线和特征的元素。最后，我们计划进行一项新颖的实验，使用英国最强大的激光(火神设备)来模拟星系中心的气体物理。激光可以产生足够大的x射线通量，以至于条件相同，我们可以第一次测试世界领先的计算机代码，该代码用于模拟靠近黑洞的星系的中心区域。

Supernovae create the heavy chemical elements we see in our solar system, the Galaxy and entire visible Universe. While stars evolve over millions or billions of years, a supernova explosion happens in seconds and the glowing remnant lasts for years. We aim to understand how these explosions happen and how they create the neutron stars, pulsars and black holes in our galaxy. The cores of massive stars collapse at the end of their nuclear burning life and the gravitational potential energy released drives an explosion through the interaction of neutrinos with the dense inner region of the star. How the most massive stars explode, and if a black hole is formed, is uncertain and there is a huge diversity in the energy observed in the known supernova population. Our proposed work will address these questions along with trying to find the sources that may create gravitational waves in the Universe. The most likely sources are merging neutron stars or black holes and it is expected that gravitational waves will finally be found. The question will then turn to finding the sources. The thermonuclear supernovae that are used as cosmic yardsticks and led to the Nobel Prize winning discovery of dark energy come from white dwarf stars. But how they explode and what the progenitor systems are still eludes us. Competing models of two merging white dwarfs, or single white dwarfs with a normal stellar companion are still feasible. Most likely there are several ways to explode a white dwarf - a star greater than the mass of the sun, but the size of the earth. We are in an excellent position to make advances in these areas with our theoretical computer codes and world leading sky survey data. The elements created in supernovae form planetary systems in our galaxy - iron, silicon, oxygen, magnesium are all critical to forming planetary systems. The diversity in the known planetary systems around other stars in our galaxy (called exoplanets) is astounding. We know of thousands of exoplanets, with massive hot jupiters, multiple planetary systems and super-earths now commonly found. We can see planet formation in the disks of young stars during their first few million years of life. The latest large facility built in the southern hemisphere (ALMA), has provided spectacular data on proto-planetary disks and our work on the chemistry of the disk aims to understand their origins. Our work will probe the atmospheres of these distant worlds by carefully extracting the light that passes from the parent star through the atmosphere of the planet. We can also measure the ages of stars to set constraints on how planetary systems evolve with time and what the constraints for life bearing planets may be. The top priority in this area is to find another earth like planet - the right size, age and distance from its parent star to support an atmosphere and liquid water. This search requires careful consideration and tests of the methods to extract the tiny signals we expect and we propose to develop this with an eye on the future prize of detecting an earth twin. A critical part of astrophysics is pulling together our detailed knowledge of physics that we can measure on earth to what we can only see (through electromagnetic radiation) in the distant Universe. This will be done through computer calculations of model atoms. These codes calculate how electrons are excited in atoms and ensures that astrophysics codes identify the elements that cause the spectral lines and features we see in supernovae, supermassive black holes, galaxy spectra and stars. Finally, we propose to run a novel experiment to use the UK's most powerful laser (the VULCAN facility) to mimic the physics of gas at the centre of a galaxy. The laser can produce a large enough x-ray flux that the conditions are equivalent and we, for the first time, can test the world's leading computer code that is used to model the central regions of galaxies close to their black holes.