The Milky Way and its neighbours in the era of large surveys

大巡天时代的银河系及其邻居

• 批准号: RGPIN-2018-03853
• 负责人: McConnachie, Alan
• 金额: $ 3.64万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712402
• 关键词: Milky; Way; its; neighbours; era

Recent maps of the distribution of stars in the outskirts of the Milky Way and Andromeda galaxies are a startling visual demonstration of the immense complexity of galaxies at large distances from the centre. They show dwarf galaxies, as well as stellar streams and other diffuse structures, as part of the same ``galactic ecosystem'', whereby interactions between galaxies and the merging of smaller galaxies into larger galaxies appear to represent part of the life-cycle of these objects. New and upcoming facilities - most immediately Gaia, as well as LSST and TMT - provide remarkable opportunities for qualitative progress in better understanding this ecosystem, the role of dwarf galaxies within it, and its consistency (or otherwise) with the cosmological paradigm. A core goal of my research is to exploit opportunites presented by Gaia, and to prepare for these upcoming scientific, technological and data opportunities through a research program centered around graduate student training. Specifically, my students will use large survey datasets for which I am PI, and that are uniquely taylored to specific studies of the nearest galaxies that cannot otherwise be addressed by the international community. My research program straddles aspects of stellar astrophysics, galaxy evolution, and cosmology. It is well established that the large scale structure of the Universe is well described by the prevailing cosmological paradigm, and it indicates that mass in the Universe is "dark" (i.e., it does not emit electromagnetic radiation). We infer its presence, however, by its gravitational influence on luminous matter, and all galaxies are expected to form within dark matter concentrations called "halos". The onus is now on researchers to test this paradigm on smaller spatial scales for which the theory was not originally developed. Here, there are well-founded, testable, predictions, but unravelling these from the complex physics of galaxy formation is observationally very difficult. The nearest galaxies offer the best opportunities for many of the relevant observations. For example, galaxy halos are intrinsically very faint, since despite being home to most of the mass of the galaxy they have very few stars with which we can hope to trace the underlying dark matter. Further, it is only for the nearby Universe that we can access the smallest ("dwarf") galaxies that provide some of the most significant challenges for the cosmological paradigm, and which appear to be the most dark-matter dominated systems that exist. I lead several programs that are aimed at providing essential data on the properties of dwarf galaxies and on the properties of galaxy halos. My overall research program is centred around graduate student training and utilizes high level access to these internationally competitive observational datasets and facilities to advance this burgeouning field.

最近绘制的银河系和仙女座星系外围的恒星分布图，从视觉上惊人地展示了离中心很远的星系的巨大复杂性。他们展示了矮星系，以及恒星流和其他弥散结构，作为同一个“星系生态系统”的一部分，据此星系之间的相互作用和较小星系合并为较大星系似乎代表了这些物体生命周期的一部分。新的和即将到来的设施——最直接的是盖亚，以及LSST和TMT——为更好地理解这个生态系统、矮星系在其中的作用以及它与宇宙学范式的一致性（或其他）提供了显著的定性进展机会。我研究的一个核心目标是利用盖亚带来的机会，并通过一个以研究生培训为中心的研究项目，为即将到来的科学、技术和数据机会做好准备。具体来说，我的学生将使用大型调查数据集，我是PI，这些数据集是专门针对最近星系的具体研究而定制的，否则国际社会就无法解决这些问题。