The assembly history of the Milky Way halo

银河系晕的组装历史

• 批准号: 2302691
• 金额: --
• 依托单位: Liverpool John Moores University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2302691
• 关键词: assembly; history; Milky; Way; halo

This project aims to constrain the early assembly history of the Milky Way by studying the chemistry and kinematics of the stellar populations in its halo. Initially we will constrain the origin of N-rich stars in the inner halo of the Galaxy, and following that we will conduct a combined observational and theoretical approach in order to establish the nature of the in-situ halo. In the first stage we will compare the chemistry and kinematics of N-rich stars with those of various Galactic components and/or accreted systems. This will be done using latest APOGEE abundances, GAIA proper motions and Gaia-based distances. The thick and thin disk will be selected on the basis of chemistry, following previous work from our group (Mackereth et al., 2018). Stars belonging to accreted systems (Gaia Enceladus and Sequoia) will be selected using the definitions from Helmi et al (2018) and Myeong et al (2019). Orbital parameters will be obtained using the python package 'gaply' (Bovy 2015). To study the in-situ halo, a selection of high-resolution simulations of Milky Way like galaxies will be examined in search for the presence of the 'Splash' population, which has been claimed to result from the impact of an early accretion event. Once such populations are identified in the simulations we will devise tests aimed at establishing their presence in data from APOGEE and WEAVE surveys. The final part of the project will involve looking into the survey data for the predicted signatures of 'simulated splashes'. This will be based on a combination of the APOGEE DR17 data (whose public data release will happen in Summer/2021) and hopefully WEAVE (expected first light 2020).

该项目旨在通过研究其光环中恒星种群的化学和运动学来限制银河系的早期组装历史。最初，我们将限制富含N的恒星在银河系的内部光环中的起源，然后我们将进行一种合并的观察和理论方法，以确定原位光环的性质。在第一阶段，我们将比较富含N的恒星的化学和运动学与各种银河系和/或积聚系统的恒星。这将使用最新的Apogee丰度，Gaia适当的运动和基于Gaia的距离来完成。在我们小组先前的工作之后，将根据化学选择厚而细的磁盘（Mackereth等，2018）。将使用Helmi等人（2018）和Myeong等人（2019年）的定义选择属于增生系统（Gaia Ecceladus和Sequoia）的恒星。轨道参数将使用python软件包“ Gaply”获得（Bovy 2015）。为了研究原位光环，将检查对银河系等银河系的高分辨率模拟，以寻找“飞溅”人群的存在，这是由于早期增生事件的影响而造成的。一旦在模拟中确定了此类人群，我们将设计旨在在Apogee和编织调查数据中确定其存在的测试。该项目的最后一部分将涉及研究“模拟飞溅”的预测签名的调查数据。这将基于Apogee DR17数据的组合（其公共数据发布将在2021年/2021年发生）并希望编织（预计2020年第一个光线）。