The evolution of the dynamics and chemistry of star forming galaxies across cosmic time

整个宇宙时间恒星形成星系的动力学和化学演化

• 批准号: 2711100
• 金额: --
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2711100
• 关键词: evolution; dynamics; chemistry; star; forming

The Hubble-Sequence of galaxy morphologies remains one of the defining characteristics of galaxies, and provides one of the key constraints that galaxy formation models strive to reproduce. Dynamical studies of local galaxies have shown that the Hubble Sequence of galaxy morphologies follows a sequence of increasing angular momentum at a fixed mass. In the cold dark matter paradigm, galaxies form at the centres of dark matter halos. As the gas collapses within the dark halo, the baryons can both lose and gain angular momentum. If the angular momentum of the baryons is (weakly) conserved during collapse, they will form a centrifugally supported disk with an exponential light profile (e.g. a spiral galaxy). If the angular momentum is redistributed (due to mergers and/or strong outflows), the morphology of the galaxy is more likely to represent a early-type or elliptical galaxy. While the role of angular momentum in locating galaxies along the Hubble-Sequence is well constrained at z=0, how the baryonic angular momentum evolves with cosmic time, and results in the emergence of the Hubble-Sequence at high redshift has not been established. Observations from the Hubble Space Telescope (HST) have shown that the transition from a galaxy population dominated by clumpy, irregular morphologies to smoother, disk-like galaxies appears to occur around z=1.5, and this has been heralded as the epoch when the Hubble Sequence "emerged", In this project, we will conduct an observational program to measure the gas properties and star formation properties in a sample of galaxies at z=1-3 (i.e. lookback times of 7-10 billion years). We will measure the role of baryons, dark matter, disk turbulence, and gas inflows and outflows in defining the formation of the galaxies. We will address the following inter-related questions: 1. How does the angular momentum of high-redshift galaxy disks result in the emergence of the Hubble-Sequence? 2. How do the dark matter fractions of galaxies evolve with mass and redshift? 3. What physical processes control the formation and evolution of star-forming regions and the gas disk? 4. Where do star-forming winds originate and how much mass and angular momentum do they carry? This is an observationally-driven PhD project. The successful student will use a range of observational facilities, potentially including travel to Chile, Hawaii or Europe to obtain data for their thesis. The PhD will provide training in the reduction and analysis of imaging, integral field spectroscopy and interferometry There will also be opportunities to relate the observational results to theoretical models being developed at Durham.

哈勃序列的星系形态仍然是星系的定义特征之一，并提供了星系形成模型努力重现的关键约束之一。局部星系的动力学研究表明，哈勃序列的星系形态遵循一个序列的增加角动量在一个固定的质量。在冷暗物质范例中，星系形成于暗物质晕的中心。当气体在暗晕内坍缩时，重子既可以失去角动量，也可以获得角动量。如果重子的角动量在坍缩过程中是（弱）守恒的，它们将形成一个具有指数光分布的离心支撑盘（例如螺旋星系）。如果角动量重新分布（由于合并和/或强烈的外流），星系的形态更可能代表早期类型或椭圆星系。虽然角动量在定位沿着哈勃序列的星系中的作用在z=0时受到很好的限制，但重子角动量如何随宇宙时间演化，并导致在高红移时哈勃序列的出现还没有确定。哈勃太空望远镜（HST）的观测表明，从一个由不规则的不规则形态主导的星系群到更平滑的盘状星系的转变似乎发生在z=1.5左右，这被预示为哈勃序列“出现”的时代，在这个项目中，我们将进行一项观测计划，测量z=1-3的星系样本中的气体性质和星星形成性质（即70 - 100亿年的回顾时间）。我们将测量重子，暗物质，盘湍流和气体流入和流出在定义星系形成中的作用。我们将讨论以下相互关联的问题：1。高红移星系盘的角动量如何导致哈勃序列的出现？2.星系中的暗物质组分是如何随着质量和红移而演化的？3.什么物理过程控制着恒星形成区和气体盘的形成和演化？4.恒星形成风起源于哪里？它们携带了多少质量和角动量？这是一个观察驱动的博士项目。成功的学生将使用一系列的观测设施，可能包括前往智利，夏威夷或欧洲，以获得他们的论文数据。博士将提供培训，减少和分析成像，积分场光谱和干涉测量也将有机会将观测结果与正在达勒姆开发的理论模型。