GalaHAD: Galaxy Formation With High Accuracy Dynamics

像银河系这样的大型恒星形成盘状星系是宇宙中最引人注目和最美丽的天体之一，它们的特征通常是令人惊叹的旋臂。了解这些迷人的星系是如何排列成现在的状态的，是现代天体物理学的中心目标之一。在我提出的研究中，我将在更大的宇宙环境中以前所未有的分辨率创建和分析模拟，以了解我们银河系的形成是如何展开的。我们的家，银河系，包含了大约1000亿颗恒星。这些恒星中的大多数都位于暗物质的巨大“光晕”的中间，而暗物质是星系形成的坩埚。这些光晕与宇宙的大规模丝状结构（被称为宇宙网）相连，光晕从中获得气体和被称为卫星的较小星系。在超过130亿年的时间里，星系通过从晕状物中吸积这些物质而成长，将气体转化为恒星，然后这些恒星在许多复杂的、高度动态的过程中移动，比如气体吸积、合并和旋臂。我们不能直接观察到这种演变，但是天文学家现在能够高度精确地测量大量恒星的位置、化学成分、运动和年龄。这些“化石记录”信息为恒星的诞生条件提供了重要线索，根据它们的起源和年龄，以及它们在宇宙时间中的演化方式，恒星的诞生条件可能会有很大的不同。通过绘制许多恒星的这些信息，天文学家可以拼凑出像银河系这样的星系是如何像宇宙拼图一样形成的。这一巨大挑战的复杂性需要复杂的理论模型来解释这些观测结果——这是我们宇宙故事的最后一个快照。然而，现在的模拟是一个巨大的挑战，既要模拟更大的宇宙环境，又要在高水平的细节上模拟中央螺旋星系，以解决望远镜现在看到的复杂的银河系结构和恒星群。为了绕过这个障碍，我将采用新的建模技术，将星系的恒星和暗物质成分的分辨率大幅提高到前所未有的水平。这些模拟将解决以前无法获得的详细的、高度动态的结构，并将使我们能够比以往更详细地跟踪大爆炸以来发生的许多复杂的物理过程。特别是，我们将了解我们美丽的旋臂是如何形成的，它们是如何在宇宙时间内将银河系周围的恒星打乱的，以及古代银河系中发生的史诗般的星系碰撞如何塑造了它今天的样子。此外，这些模拟将打开一扇新的窗口，让我们了解潜伏在银河系周围的非常小的、低质量的星系的形成，将我们目前的知识推向新的视野。观测需要这些模拟来解释。由于我们目前生活在一个大型观测调查的黄金时代，这将提供越来越多的信息，因此现在必须执行这个项目，以便最大限度地从这些观测中获得回报。通过对我的模拟进行模拟观察，我们可以直接将模拟结果与观测结果进行比较，从而全面了解银河系是如何形成的。我们还将学习恒星的运动如何告诉我们暗物质粒子的性质。这些深奥问题的答案将极大地有利于人类对宇宙及其奥秘的好奇心，并激励社会上的下一代科学家。这些模拟将被公开，并将成为其他天文学家的宝贵资源，并产生我们宇宙家园起源和形成的最详细的图像和电影。

Large star-forming disc galaxies like the Milky Way are some of the most striking and beautiful objects in the Universe, often characterised by their breathtaking spiral arms. Understanding how these fascinating systems arranged themselves into their present state is one of the central aims of modern astrophysics. In my proposed research I will create and analyse simulations with unprecedented resolution within the larger cosmological environment in order to understand how the formation of our Galaxy unfolded.Our home, the Milky Way galaxy, contains about 100 billion stars. The majority of these stars are in the middle of a large "halo" of dark matter, the crucibles in which galaxies are forged. These haloes are connected to the large-scale filamentary structure of the Universe, dubbed the Cosmic Web, from which haloes acquire gas and smaller galaxies known as satellites. Galaxies grow by accreting this material from their haloes over more than 13 billion years, transforming gas into stars which then move around in response to many complex, highly dynamical processes like gas accretion, mergers and spiral arms. We cannot observe this evolution directly, but astronomers are now able to measure the locations, chemical composition, motions, and ages for a large number of stars to a high degree of accuracy. This "fossil record" information provides vital clues to the birth conditions of stars, which can be very different depending on their origin and age, and how they evolved over Cosmic time. By mapping out this information for many stars, astronomers can piece together how galaxies like the Milky Way formed like a cosmic jigsaw.The complexity of this great challenge demands sophisticated theoretical models to interpret these observations - the final snapshot in our Cosmic story. However, it is now an enormous challenge for simulations to model both the larger cosmological environment and the central spiral galaxy at the high level of detail necessary to resolve the intricate Galactic structure and its stellar populations that telescopes are now seeing. To get around this roadblock, I will employ new modelling techniques to dramatically enhance the resolution of the stellar and dark matter components of the galaxy to unprecedented levels. These simulations will resolve detailed, highly dynamical structures that were previously inaccessible, and will allow us to follow the many complex physical processes that have occurred since the Big Bang in more detail than ever before. In particular, we will learn how our beautiful spiral arms formed, how they shuffled stars around our Galaxy over Cosmic time, and how epic galaxy collisions that occurred in the ancient Milky Way shaped how it looks today. Additionally, these simulations will open a new window into the formation of very small, low-mass galaxies that lurk in the surroundings of the Milky Way, pushing our current knowledge to new horizons.Observations require these simulations for their interpretation. Because we currently live in a golden era of large observational surveys which will provide increasing amounts of information, it is essential to carry out this project now in order to maximise our return from these observations. By making mock observations from my simulations, we can compare the simulations directly to observations to provide a holistic view of how the Milky Way formed. We will also learn how the motions of stars can inform us about the nature of the dark matter particle. Answers to these profound questions will greatly benefit mankind's curiosity of the Universe and its mysteries, and inspire future generations of scientists within society. These simulations will be made publicly available and will become a valuable resource for other astronomers, and produce the most detailed images and movies currently available of the origin and formation of our cosmic home.