Decoding the structure and formation history of the Milky Way halo with non-equilibrium orbit-based models

用非平衡轨道模型解码银河系晕的结构和形成历史

• 批准号: ST/X004066/1
• 负责人: Eugene Vasiliev
• 金额: $ 81.09万
• 依托单位: University of Surrey
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FX004066%2F1
• 关键词: Decoding; structure; formation; history; Milky

The field of Galactic astronomy is flourishing thanks to enormous advances in observational facilities in recent years, however, the progress in the theoretical analysis and interpretation of the detailed observational picture is lagging behind.The outer parts of our Galaxy (the halo) are dominated by stars originating in other stellar systems engulfed by the Milky Way in the past, which retain important clues about the Galactic assembly history and properties of ancient accreted galaxies. These building blocks are usually identified by their coherent spatial, kinematic and chemical properties, but linking the populations of same-origin stars across the entire Galaxy is only possible with the knowledge of their orbits, which in turn depend on the gravitational potential. In turn, the orbital coherence of structures such as stellar streams is used to constrain the Galactic potential and hence the distribution of stars and dark matter, but current methods are usually restricted to stationary potentials. However, the ongoing encounter between our Galaxy and its largest satellite - the Large Magellanic Cloud - introduces significant temporal variations in the potential, disturbs the kinematics of halo stars and confounds the analysis.My project will provide solid theoretical foundation and analysis techniques for the current and upcoming large-scale surveys of the Milky Way system, and will shed light on its structure and formation history with the help of next-generation models. It will combine the techniques for finding localized structures with the underlying physical model for the evolving global gravitational field of the entire Galaxy, enabling for the first time to simultaneously identify and characterize the individual building blocks and constrain the time-dependent Galactic mass distribution. It will advance our understanding of the past and present of the Milky Way, and pave the road to a detailed exploration of other galaxies in the local Universe.

近年来，由于观测设施的巨大进步，银河天文学领域正在蓬勃发展，然而，对详细观测图像的理论分析和解释的进展却相对滞后。我们银河系的外部部分（晕）主要由起源于过去被银河系吞没的其他恒星系统的恒星，保留了有关银河系组装历史和古代吸积星系性质的重要线索。这些构建块通常通过其连贯的空间、运动学和化学特性来识别，但只有了解它们的轨道，才能将整个银河系中的同源恒星群体联系起来，而轨道又取决于引力势。反过来，恒星流等结构的轨道相干性被用来限制银河势，从而限制恒星和暗物质的分布，但目前的方法通常仅限于固定势。然而，我们的银河系和它最大的卫星——大麦哲伦星云之间的持续相遇，引入了势能的显着时间变化，扰乱了晕恒星的运动学，并混淆了分析。我的项目将为当前的情况提供坚实的理论基础和分析技术。以及即将进行的大规模银河系调查，并将借助下一代模型揭示其结构和形成历史。它将寻找局部结构的技术与整个银河系不断演变的全球引力场的底层物理模型相结合，首次能够同时识别和表征各个构建块，并限制与时间相关的银河质量分布。它将增进我们对银河系过去和现在的理解，并为详细探索当地宇宙中的其他星系铺平道路。