Constraining the structure and history of the Milky Way disk using Gaia

由于我们的接近，银河系提供了一个独特的实验室来研究一个巨大的盘状星系的细节。我们目前生活在银河系考古学的黄金时代，能够使用多个恒星群体来研究我们银河系的形成历史和结构，包括运动学，化学丰度和非常精确的年龄估计。随着欧空局盖亚使命最近发布的第二次和第三次早期数据（DR 2和EDR 3），这一领域发生了范式转变。在恒星多维化学丰度和运动学相空间中已经进行了前所未有的详细诊断。这引发了关于盘的动力学状态、旋臂和中央棒的性质以及合并卫星的影响（例如，人马座矮星系）。该提案的目标是通过使用最先进的数值模型来解释盖亚DR 3数据，结合现有和即将到来的地基光谱数据（APOGEE，SDSS-V，GALAH和WEAVE，4 MOST）以及来自CoRoT，Kepler和K2任务的小行星地震数据，来限制银河系盘的关键结构特性和形成。化学丰度和精确的年龄可以与恒星的诞生位置相关，这对于区分竞争模型非常重要。我们的模型将主要基于即将在AIP进行的高分辨率HESTIA模拟，该模拟使用最先进的AREPO/御夫座星系形成代码在本星系群环境中模拟银河系。在模型和数据之间的比较中，我们将考虑选择效应和观测误差。我们将通过考虑以下相互关联的问题，为不同的银河系演化场景提供测试：（1）理解Gaia DR 2数据中发现的丰富相空间结构（脊，拱门，蜗牛壳螺旋在速度位置空间）在最近的扰动从下落星系和内部代理人（棒臂和旋臂），（2）通过研究单一年龄组恒星的盘厚度和速度色散径向分布以及轨道特性随年龄的变化，恢复银河系盘的长期合并历史，（3）结合动力学、化学和年龄信息，在宇宙学背景下考虑现实的时间演化模型，约束银河系棒旋结构参数。

Due to our proximity, the Milky Way provides a unique laboratory to study a massive disk galaxy in exquisite detail. We are currently living in the golden age of Galactic Archaeology, being able to investigate the formation history and structure of our Galaxy using multiple stellar populations with kinematics, chemical abundance, and age estimates with excellent precision. A paradigm shift has occurred in this field with the recent second and early third data releases (DR2 and EDR3) from ESA’s Gaia mission. Detailed diagnostics as never before have already been performed in the stellar multi-dimensional chemical abundance and kinematics phase space. This has fueled controversies about the dynamical state of the disk, the nature of spiral arms and central bar, and the effect of merging satellites (e.g., the Sagittarius dwarf galaxy). The goal of the proposal is to constrain key structural properties and the formation of the Milky Way disk, by using state-of-the-art numerical models for the interpretation of the Gaia DR3 data, combined with available and upcoming ground-based spectroscopic data (APOGEE, SDSS-V, GALAH and WEAVE, 4MOST), as well as the asteroseismic data from CoRoT, Kepler, and K2 missions. Chemical abundances and precise ages can be related to the birth positions of stars, which is extremely important for discriminating among competing models. Our models will be mostly based on the upcoming high-resolution HESTIA simulations at the AIP, which simulate the Milky Way in the Local Group environment using the state-of-the-art AREPO/Auriga galaxy formation code. In the comparison between models and data we will account for both selection effects and observational errors. We will provide tests for different Milky Way evolutionary scenarios by considering the following interconnected problems: (1) Understand the rich phase-space structure found in the Gaia DR2 data (ridges, arches, and snail-shell spiral in velocity-position space) in terms of recent perturbations from infalling galaxies and from internal agents (bar and spiral arms), (2) Recover the extended merger history of the Milky Way disk by studying disk thickness and velocity dispersion radial profiles for mono-age groups of stars, as well as changes in orbital properties with age, and (3) Constrain the Milky Way bar and spiral structure parameters by considering realistic time-evolving models in the cosmological context and combining dynamics, chemistry and age information.