Modelling the most extreme high redshift galaxies: from star formation rates to supermassive black hole growth

模拟最极端的高红移星系：从恒星形成率到超大质量黑洞的生长

• 批准号: 2445116
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2445116
• 关键词: Modelling; most; extreme; redshift; galaxies

Extremely luminous InfraRed and SubMm galaxies ((U)LIRGS and SMGs) are routinely detected with star formation rates in excess of 100 - 1000 solar masses per year at intermediate and high redshift (z>1). Morphological studies have shown that these galaxies appear to be a mix of merging/interacting systems and disk galaxies. Continuous gas accretion via cold streams has also been invoked as a means to sustain their elevated star formation rates over significantly long periods of time. Furthermore these galaxies are thought to host some of the most massive supermassive blackholes (SMBH) in the Universe, at a time when their energy input into the circum-galactic medium (so called Active Galactic Nuclei (AGN) feedback) is the largest. However, these objects have proven notoriously challenging to model, as they are very rare in the local Universe and hence necessitate running very large volume cosmological simulations whilst still resolving the interstellar medium (ISM) of the galaxy and the central region surrounding their SMBH. Making the modelling even more challenging is increasing evidence that cosmic rays and magnetic fields are strong players in galaxies with extreme star formation rates. To overcome these difficulties, this DPhil project proposes to extract a sample of rare objects from a gigaparsec cube dark matter only simulation and re-simulate them with spatial resolution fine enough to resolve the giant molecular clouds that form in their ISM, including cosmic rays and magnetic fields. Armed with this series of simulations the student will explore (i) how the environmental history of high redshift extreme star forming galaxies and the interaction between the different feedback mechanisms (stellar winds, supernovae, AGN, galactic winds possibly powered by cosmic rays) impact their star formation rates, (ii) whether ISM properties of simulated extreme galaxies match observed ones, and especially (iii) how energy is apportioned between thermal/turbulent/magnetic/cosmic ray energies and whether this regulates star formation. For this purpose, special attention will be given to outflows, in particular we will seek to determine their powering source (stellar or AGN feedback) and chemical composition (hot ionised or cold molecular gas). Comparison to spatially resolved kinematic observations will be carried out through emission line diagnostics.This research falls within STFC's science programme challenge A: "How did the Universe begin and how it is evolving?", and more specifically sub-challenges A.4: "When and how were the first stars, black holes and galaxies born?" and A.5: "How do stars and galaxies evolve?".

在中间和高红移（Z> 1）时，常规检测到极发光的红外线（（U）LIRGS和SMG），每年超过100-1000太阳能（Z> 1），常规检测到超过100-1000个太阳能。形态学研究表明，这些星系似乎是合并/相互作用系统和磁盘星系的混合。通过冷流进行连续的气体吸积也已被援引，以维持其在很长一段时间内保持其恒星形成率升高的一种手段。此外，这些星系被认为是宇宙中一些最庞大的超级黑洞（SMBH），当时它们的能量输入到圆周培养基中（所谓的主动银河核（AGN）反馈）是最大的。但是，这些物体在当地宇宙中非常罕见，因此已被证明是众所周知的挑战，因此需要进行非常大的宇宙学模拟，同时仍在解决银河系的星际介质（ISM）和SMBH周围的中央区域。使建模更具挑战性的是越来越多的证据表明，宇宙射线和磁场是具有极端恒星形成率的星系中的强大参与者。为了克服这些困难，该DPHIL项目提议从Gigaparsec Cube暗物质中提取稀有物体的样本，仅模拟它们，并用足够细的空间分辨率重新仿真，以解决在其ISM中形成的巨型分子云，包括宇宙射线和磁场。学生将在这一系列的模拟中探索（i）高红移极端星形形成星系的环境历史以及不同反馈机制（恒星风，超新星，AGN，银河风，可能由宇宙射线供电的驱动力）之间的相互作用之间的恒星形成率，（ii）是否尤其是符合的（II）。热/湍流/磁/宇宙射线能量以及是否调节恒星形成。为此，将特别注意流出，特别是我们将寻求确定其动力来源（出色或AGN反馈）和化学成分（热离子化或冷分子气）。与空间解决的运动学观测相比，将通过发射线诊断进行。这项研究属于STFC的科学计划中的研究挑战：“宇宙是如何开始的，它是如何发展的？”，更具体地说，更具体地说是亚挑战者A.4：“何时，何时和如何出生？”和A.5：“星星和星系如何发展？”。