Next generation hydrodynamic simulations of galaxy clusters

星系团的下一代流体动力学模拟

• 批准号: 2904304
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2904304
• 关键词: Next; generation; hydrodynamic; simulations; galaxy

Galaxy clusters host the most massive galaxies in the Universe, with stellar masses up to one trillion times the mass of the Sun. These galaxies are surrounded by huge reservoirs of hot, X-ray emitting plasma, with temperatures over 10 million Kelvin. A puzzling observation, however, is that this gas is not cooling down and forming new stars at the expected rate - why does star formation shut down in massive galaxies? One, currently favoured, answer is that the gas is being kept hot by an active galactic nucleus (AGN) through the emission of powerful jets of radio-bright relativistic plasma. The AGN, powered by accretion on to a super-massive black hole, is energetically capable of counteracting the radiative losses in the X-ray gas and can even drive some of the gas out of the system altogether. Modern hydrodynamic simulations of galaxy clusters attempt to include the effects of this so-called AGN feedback process and can successfully model the shut-down of star formation in brightest cluster galaxies, while producing black holes with observationally-reasonable masses. However, these simulations currently struggle to reproduce the X-ray thermal properties of the gas, predicting material that tends to be too hot and diffuse in the cluster core. Such a discrepancy is likely the result of current models not capturing all the essential physics but may also be due to insufficient numerical resolution. In this PhD project, the student will join ongoing collaborative efforts to develop a new generation of cluster simulations with improved resolution and physics modelling using the SWIFT hydrodynamics code (swift.dur.ac.uk). They will work on science projects involving the analysis of new simulation data as well as have the opportunity to help develop and test new simulation models. The student will join the Virgo consortium and use the DiRAC high performance computing facility (dirac.ac.uk).

星系团拥有宇宙中最大的星系，恒星质量高达太阳质量的一万亿倍。这些星系被巨大的热的X射线发射等离子体所包围，温度超过1000万开尔文。然而，一个令人困惑的观察结果是，这种气体并没有以预期的速度冷却和形成新的恒星-为什么星星的形成在大质量星系中关闭？目前比较流行的一种解释是，活动星系核（AGN）通过放射出强大的射电明亮的相对论等离子体喷流来保持气体的温度。活动星系核由超大质量黑洞的吸积提供动力，它在能量上能够抵消X射线气体中的辐射损失，甚至可以将一些气体完全赶出系统。 现代星系团的流体动力学模拟试图包括这种所谓的活动星系核反馈过程的影响，并可以成功地模拟最明亮的星系团星系中星星形成的关闭，同时产生具有观测合理质量的黑洞。然而，这些模拟目前很难再现气体的X射线热性质，预测材料往往太热并在团簇核心扩散。这种差异很可能是当前模型没有捕捉到所有基本物理的结果，也可能是由于数值分辨率不足。在这个博士项目中，学生将加入正在进行的合作努力，开发新一代的集群模拟，使用SWIFT流体动力学代码（swift.dur.ac.uk）提高分辨率和物理建模。他们将从事涉及新模拟数据分析的科学项目，并有机会帮助开发和测试新的模拟模型。学生将加入Virgo联盟，并使用DiRAC高性能计算设施（dirac.ac.uk）。