Direct Modeling of Star Clusters in Galaxy Formation Simulations

星系形成模拟中星团的直接建模

• 批准号: 1412144
• 负责人: Oleg Gnedin
• 金额: $ 30.23万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1412144&HistoricalAwards=false
• 关键词: Direct; Modeling; Star; Clusters; Galaxy

The scientists will numerically simulate the origin of star populations in our Galaxy. The study will include a novel approach to modeling star clusters directly in galaxy formation simulations. They seek to unravel several unsolved puzzles in our understanding of Galactic formation and evolution: (i) What caused multiple generations of stars within massive globular clusters? (ii) What is the fraction of halo stars stripped off globular clusters? (iii) Was the bulge assembled by early mergers or by gradual transformation of the Galactic disk? They will implement the cluster formation and evolution model in the cosmological adaptive-mesh-refinement code (called ART) and run several realizations of Milky Way-sized galaxies with different environment and merger history. ART is a powerful galaxy formation code and already includes non-equilibrium cooling and heating of cosmic gas, non-equilibrium formation and dissociation of molecular hydrogen, thermal, kinetic, and radiative feedback of young stars, transport of ionizing radiation, and other important processes. Inclusion of clustered star formation will add a realistic description of stellar populations, with a well-defined stellar initial mass function and more concentrated feedback on the interstellar medium (ISM). The simulations will produce a rich data model, and will be used to interpret various observations of Galactic clusters and dwarf satellites.They will integrate the simulations into a program of state-of-the-art scientific visualizations of galaxy formation over cosmic time. The visualizations will be designed for display at the University of Michigan Planetarium, and will be viewed by thousands of elementary, middle and high school students in the Detroit metropolitan area.

科学家们将对银河系中恒星群的起源进行数值模拟。这项研究将包括在星系形成模拟中直接模拟星团的新方法。他们试图解开我们对银河系形成和演化的理解中几个尚未解决的谜题：(i)是什么导致了大质量球状星团内多代恒星的形成？（ii）从球状星团中剥离出来的晕星的比例是多少？（iii）凸起是由早期合并形成的，还是由银盘的逐渐转变形成的？他们将在宇宙学自适应网格细化代码（称为ART）中实现星团形成和演化模型，并运行具有不同环境和合并历史的银河系大小星系的几种实现。ART是一个强大的星系形成代码，已经包括了宇宙气体的非平衡冷却和加热，分子氢的非平衡形成和解离，年轻恒星的热、动力学和辐射反馈，电离辐射的输运以及其他重要过程。包含星团形成将增加对恒星种群的真实描述，具有定义良好的恒星初始质量函数和更集中的星际介质（ISM）反馈。模拟将产生一个丰富的数据模型，并将用于解释对星系团和矮卫星的各种观测。他们将把模拟整合到一个最先进的星系形成可视化程序中。这些可视化图像将在密歇根大学天文馆展出，并将由底特律大都会地区数千名小学、初中和高中学生观看。