A Holistic Approach to Modeling Galaxy Groups and Clusters

星系团和星系团是非凡的系统。这些系统的质量从相当于1万亿个太阳到令人难以置信的亿亿个太阳，是宇宙中最大、质量最大的引力束缚物体。它们因富含明亮星系而引人注目，是宇宙中最明亮的x射线源之一。因此，它们很容易在很远的地方被识别出来。它们也是已经形成的最年轻的宇宙结构，因此，它们仍然带有导致它们形成的条件的印记。由于所有这些因素，这些系统中质量最大的被认为是宇宙几何和膨胀的潜在强大探测器。然而，星系团作为宇宙探测器的使用，关键取决于我们对当地宇宙中星系团和星系团的理解程度，以及这些系统在更早时期的样子。我的研究重点是这两个问题。我正在开发现实的预测模型来详细描述群体和集群是如何形成的，以及它们是如何随时间变化的。建模涉及使用最先进的计算机模拟，在强大的超级计算机上进行，以“虚拟地”复制宇宙137亿年的历史，并确定导致我们今天观察到的系统的条件。随着时间的推移，群体和星团受到一个相互影响的复杂过程网络的影响，比如那些控制恒星的诞生、生命和死亡的过程，那些塑造聚集暗物质流的消长和流动的过程，这些过程会随着时间的推移产生越来越大的宇宙结构，还有那些控制超大质量黑洞从周围环境中捕获和吸收气体时的反应的过程。现实的数值模拟是解开这个网络的唯一方法，并使观测到的星系团和星系团的特性如何出现变得有意义。

Galaxy groups and clusters are remarkable systems. With masses ranging from an equivalent of 10,000 billion suns to a mind-boggling million billion suns, these systems are the largest, most massive gravitationally bound objects in the Universe. They stand out as rich concentrations of bright galaxies and are among the most luminous X-ray sources in the universe. As a result, they are easy to identify out to vast distances. They are also the youngest of the cosmic structures to have formed and as such, still bear the imprints of the conditions that led to their formation. Because of all these factors, the most massive of these systems have been identified as potentially powerful probes of the geometry and the expansion of the universe. However, the use of clusters as cosmological probes depends critically on how well we understand why groups and clusters in the local universe look the way they do, and what these systems would have looked like at an earlier epoch. My research focuses on these two issues. I am developing realistic predictive models to describe, in detail, how groups and clusters formed and how they have changed over time. The modeling involves using state-of-the-art computer simulations, carried out on powerful supercomputers, to replicate "virtually" the universe's 13.7 billion year history and identify the conditions that led to the systems we observe today. Over the course of time, groups and clusters are influenced by an incredibly complex web of processes all influencing one another, processes such as those that govern the birth, life and death of stars, those that shape the ebb and flow of convergent dark matter flows that give rise to increasingly larger cosmic structures with time, and those that govern the response of supermassive black holes as they capture and draw in gas from their surroundings. Realistic numerical simulations are the only way of unraveling this web and making sense of how the observed properties of galaxy groups and clusters emerged.