Connecting Dwarf Galaxies, Metal Poor Stars, and the Origins of the Elements

恒星表面含有其诞生云的化学成分的化石指纹，而贫金属恒星作为银河系形成和组装历史的追踪者尤为重要。此外，贫金属星对于理解这些元素的起源很重要，因为很少有核合成事件会对它们的化学成分产生影响。在接下来的十年中，大型高分辨率光谱、光度和天体测量将在整个银河系发现具有有趣起源和动力学的贫金属星样本。更高精度的分析将揭示它们的详细成分，使我们能够打破恒星和星系建模中的简并，探索它们的起源，并更好地理解元素的形成。这项研究计划建立在我在恒星光谱学方面的专业知识和我与原始调查的成功合作，以发现稀有金属贫恒星，从而产生两个长期目标：(1)寻找和分析整个银河系和矮星系中的贫金属星--对银河系和附近卫星中的贫金属星的研究显示，由于一系列(简并的)星系和恒星建模假设，化学丰度模式有所不同。需要更大的统计样本才能打破这些简并并绘制出贫金属的银河系。(2)理解重r过程元素的起源--元素的起源仍然是物理学中尚未解决的重大问题之一，尽管在中子星合并中发现了r过程核合成，作为无处不在的r过程位置的补充，这是一个重大突破。需要对在不同环境中形成的贫金属星进行比较，以限制这些核合成途径。这项研究计划将使用双子座天文台的GRACE和即将推出的GHOST光谱仪来获取低金属恒星的高分辨率(R&GT；50,000)光谱；对于r过程元素谱线，Ghost对于450 nm以下的光谱尤其必要。该计划还将使用即将到来的Weave光谱调查中的贫金属星(约3000个目标)的光谱。因此，对于发现和分析各种银河系环境(银河系凸起、平面、球状星团、流和矮星系)中的大量贫金属星来说，这是一个令人兴奋的时刻。我的研究计划的影响将是更好地了解重元素的起源和贫金属星系的组装历史，从而改进星系和恒星建模。该计划为HQP提供了观测和理论天体物理学方面的培训机会，以及开发新的数据分析方法(例如机器学习算法)和参与仪器开发(例如GHOST的科学验证)的独特机会，从而为未来的加拿大设施(例如TMT、MSE或类似设施)做好准备。

The surfaces of stars contain a fossil fingerprint of the chemical composition of their birth clouds, and metal-poor stars are particularly important as tracers of the formation and assembly history of the Galaxy. Moreover, metal-poor stars are important for understanding the origins of the elements given that few nucleosynthetic events would have contributed to their chemical compositions. In the upcoming decade of large high-resolution spectroscopic, photometric, and astrometric surveys, samples of metal-poor stars with interesting origins and dynamics will be discovered throughout the Milky Way. Higher precision analyses will reveal their detailed compositions, allowing us to break degeneracies in stellar and galaxy modeling, to explore their origins and better understand the formation of the elements. This research program builds on my expertise in stellar spectroscopy and my successful collaboration with the Pristine survey to find rare metal-poor stars, leading to two long term goals: (1) Finding and analyzing metal-poor stars throughout the Milky Way and dwarf galaxies - Studies of metal-poor stars in the Milky Way and nearby satellites have shown chemical abundance patterns that differ due to a range of (degenerate) galactic and stellar modeling assumptions. Larger statistical samples are required to break those degeneracies and map the metal-poor Milky Way. (2) Understanding the origins of heavy r-process elements - The origin of the elements remains one of the great unsolved problems in physics, although a major breakthrough came with the discovery of r-process nucleosynthesis in a neutron star merger, as an addition to a ubiquitous r-process site. A comparison of metal-poor stars that formed in a variety of environments is needed to constrain these nucleosynthetic pathways. This research program will use the Gemini Observatory GRACES and upcoming GHOST spectrographs for high resolution (R>50,000) spectra of metal-poor stars; GHOST is particularly necessary for spectra below 450 nm for r-process element spectral lines. This program will also use spectra of metal-poor stars (~3000 targets) from the upcoming WEAVE spectroscopic survey. Therefore, this is an exciting time for the discovery and analysis of a large number of metal poor stars, in a variety of galactic environments (Galactic bulge, plane, globular clusters, streams, and in dwarf galaxies). The impact of my research program will be a better understanding of the origin of the heavy elements and the assembly history of the metal-poor Galaxy, leading to improvements in galaxy and stellar modeling. This program provides training opportunities for HQP in observational and theoretical astrophysics, and unique opportunities to develop new data analysis methodologies (e.g., machine learning algorithms) and to be involved in instrumentation developments (e.g., science verification for GHOST), thereby preparing for future Canadian facilities (e.g., TMT, MSE, or equivalents).