Star formation in galaxies from the Epoch of Reionisation to the present day with JWST

第一批星系看起来与今天充斥在宇宙中的令人敬畏的螺旋形和椭圆形非常不同。光速有限意味着一个物体离我们越远，我们在时间上看到它的时间就越早。多亏了哈勃太空望远镜凝视着遥远的太空，这让我们得以瞥见宇宙蹒跚学步阶段的混乱、动荡和不稳定的星系。与此同时，地面和天基天文台一直在构建一幅更完整、更细微的青少年时期的图景，直到它目前相对有序的成年状态。但这张照片的大部分仍然没有找到，下一个伟大的太空天文台--詹姆斯·韦伯太空望远镜(JWST)--才能开始填充它们。我将补充的照片部分是研究从早期宇宙到今天的星系是如何形成恒星的。从组成恒星托儿所的气体的性质出发，我将研究在那个特定的恒星生成中存在哪些元素，以及从恒星如何使气体发光来了解恒星本身。我将探测平滑演化或突然变化的恒星形成的示踪物的光谱，以表明恒星形成在不同时期是多么不稳定。我将寻找吸积超大质量黑洞的迹象，这种系统如此强大，以至于我们认为它们能够加热气体，阻止更多的恒星在整个银河系形成。我们将第一次能够使用相同的观测示踪剂来进行这些研究，这些示踪剂用于解开当地影响恒星形成的因素。这项研究的一个重要目的是用一致的方法绘制出这些因素从宇宙萌芽到今天的演化。在天文学中，我们总是面临这样的问题：我们的观测只是过去的快照，我们无法追踪单个星系随时间的演化。因此，我将使用各种星系演化的流体动力学模拟来解释这个计划提供的人口统计数据。尤其重要的是，定制的Cockatoo模拟追踪了不同恒星类型中形成的金属，以及它们如何喷射到两个恒星之间的空间，准备混合、冷却并形成后续的恒星世代。

The first galaxies looked very different to the awe-inspiring spirals and ellipticals that populate the Universe today. The finite speed of light means that the further away an object is to us, the further back in time we are seeing it. This has permitted us to glimpse the messy, turbulent and erratic galaxies populating the toddler stage of the Universe, thanks to the Hubble space telescope peering into distant space. Meanwhile, ground and space based observatories have been building a more complete, nuanced picture of the teenage years through to it's current, relatively ordered, adult state. But huge chunks of the picture are still missing and it will take the next great space-based observatory, the James Webb space telescope (JWST), to start filling them in.The part of the picture I will be filling in is investigating how galaxies form their stars, from the early Universe to the present day. From the properties of the gas making up the stellar nurseries I will investigate what elements are present for that particular stellar generation, as well as learning about the stars themselves from how they make that gas shine. I will probe spectra for tracers of smoothly evolving or abruptly changing star formation, to indicate how erratic the star formation is at different epochs. I will search for signatures of accreting supermassive black holes, systems that are so powerful we think they are able to heat gas and prevent further stars from forming throughout a whole galaxy. For the first time we will be able to do these studies with the same observational tracers used to disentangle factors affecting star formation locally. A significant aim for this research is to plot the evolution of these factors from the Universe's infancy to the present day using a consistent approach.In astronomy we are always faced with the problem that our observations are but snapshots of the past, and we have no way to trace an individual galaxy's evolution with time. I will therefore be using various hydrodynamic simulations of galaxy evolution to interpret the population statistics provided by this program. Not least, the bespoke COCKATOO simulation traces metals formed within different stellar types, as well as their ejection into the space between, ready to mix, cool and form subsequent stellar generations.