Simulating the formation and evolution of galaxies and cosmic structure

我们的宇宙包含一系列惊人的可见结构，大小不一，从行星到恒星，再到星系和星系团。我们还可以遥望遥远的地方，从而回到过去，看到当前结构的早期、混乱的先驱。最终，在最远的地方，我们只看到大爆炸余辉中的微小涟漪，它们是目前所有结构的种子。这种进化是如何发生的？这个项目将宇宙放入计算机，让我们能够试验宇宙结构是如何形成、相互作用和演化的；在几个小时或几天内，我们就可以对140亿年的宇宙历史进行建模。 在许多方面，我们现在了解了宇宙结构在最大尺度、数千万光年甚至更大尺度上的分布，但对星系本身的详细了解仍然难以捉摸。然而，星系是宇宙的关键发光标志，了解它们的起源和历史是晚宇宙宇宙学的中心目标；这是我研究的重点。 星系是几个过程复杂相互作用的结果，我们必须对这些过程进行建模。引力作用于所有物质：不可见的暗物质、气体、尘埃和恒星。气体受到流体动力的影响。恒星从气态的星际介质中形成，在它们的一生中用电离辐射和风为它们的周围提供能量，在它们死亡时，它们以猛烈的爆炸将富含重元素的气体返回星际介质。我们正在开发对这些过程越来越精确的计算机模拟，最终目的是提供星系群及其形成和演化的详细模型。这项研究为天文学家目前从地面和天基天文台收集和预测的丰富观测数据提供了理论上的对应。它是加拿大数值模拟专业知识的关键驱动力，也是国际公认的加拿大探索宇宙起源的努力的一部分。

Our universe contains an astonishing array of visible structures ranging in size from planets, to stars, to galaxies and clusters of galaxies. We can also look to great distances, and hence back in time, and see the early, chaotic progenitors of current structure. Eventually, at the furthest distances we see just the small ripples in the afterglow of the Big Bang that are the seeds for all current structure. How did this evolution happen? This project puts the universe into a computer, allowing us to experiment with how cosmic structures form, interact and evolve; in hours or days we can model what has taken 14 billion years of cosmic history. In many respects we now understand the distribution of cosmic structures on the largest scales, tens of millions of light years and greater, but a detailed understanding of galaxies themselves remains elusive. Yet galaxies are the key luminous markers of the universe, and understanding their origins and histories stands as a central goal of late-universe cosmology; this is the focus of my research. Galaxies result from the complex interplay of several processes which we must model. Gravity acts on all matter: invisible dark matter, gas, dust and stars. Gas is subject to hydrodynamic forces. Stars form out of the gaseous inter-stellar medium, energize their surroundings with ionizing radiation and winds during their lives, and, at their deaths, return gas enriched with heavy elements to the inter-stellar medium in violent explosions. We are developing increasingly accurate computer simulations of these processes with the ultimate aim of providing detailed models of galaxy populations and their formation and evolution. The research provides the theoretical counterpart to the wealth of observational data that astronomers are now gathering and anticipating from ground- and space-based observatories. It is a key driver of numerical modelling expertise in Canada and forms part of the internationally recognized Canadian endeavour to uncover our cosmic origins.