Towards a Cosmological View of Disk Galaxy Structure

盘状星系结构的宇宙学观点

• 批准号: RGPIN-2014-03950
• 负责人: Spekkens, Kristine
• 金额: $ 3.06万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=665702
• 关键词: Towards; Cosmological; View; Disk; Galaxy

The broadly-accepted cosmological model for the composition and evolution of the Universe explains a remarkable range of astronomical observations. However, it is not yet clear how galaxies form and evolve within this framework, and understanding how this process happens is one of the biggest challenges in cosmology today. Detailed observations of the galaxies around our own provide important clues to the processes that create their internal structure. Spiral galaxies similar to the Milky Way are particularly useful in this regard, because their properties can be inferred from the distributions and orbital speeds of gas and stars in their disks. Detailed structural studies of nearby spiral galaxies therefore provide key evidence that allows astronomers to decipher the physics of galaxy formation and evolution. **Early comparisons between the measured structure of spiral galaxies and simple theoretical predictions found that the two were strongly discrepant. Astronomers now suspect that this disagreement arises not from a failure of cosmology, but from overlooked details of how galaxies form. It is now clear that gas and stars can alter dark matter halos during galaxy formation more efficiently than previously thought, and that the subtle interplay between different galactic components after they have formed can also drive galaxy evolution.**While several plausible mechanisms have been invoked to explain the observed structure of nearby galaxies, it is not yet clear which of them are generic during galaxy formation. Proof-of-concept comparisons between detailed cosmological simulations and handfuls of observed galaxies have been successful, but population-wide galaxy studies are still lacking. This is due in part to a dearth of high-quality orbital speed maps for nearby galaxies required for these careful comparisons. This will change in the near future with the advent of large spectroscopic surveys at different wavelengths. At the same time, the size and efficiency of modern telescopes enable exquisitely detailed studies of individual galaxies. The next few years are therefore exciting ones for galaxy formation research, since it will be possible to systematically test proposed theories for the first time. **The main objective of my research is to understand the structure of nearby spiral galaxies in a cosmological context. My research group carries out systematic structural studies of large galaxy samples using software that we have developed for this purpose. The physicality and robustness of our code are unparallelled, and our group is therefore poised to constrain the dark and luminous matter contents of thousands of nearby spiral galaxies from forthcoming surveys. My group also devises and carries out novel experiments on extreme or unique systems in the local Universe, in order to gain insight into the physics of the galaxy population as a whole. My program provides a collaborative, world-class training environment in which highly qualified personnel excel.**Canada is an international leader in astronomy, often ranking first in this field: this success engenders technology and innovation that give our country a competitive edge on the world stage. My program addresses some of the key questions that drive astronomical research: how are dark matter halos altered when spiral galaxies form within them? How do the orbits of the stars and gas in spiral galaxies drive their evolution? Is the observed structure of spiral galaxies consistent with cosmological predictions when these processes are taken into account? What is the nature of the dark matter? My work will help answer these questions, making progress towards my field's ultimate goal of developing a complete theory of cosmological galaxy formation and evolution.

被广泛接受的宇宙组成和演化的宇宙学模型解释了一系列显著的天文观测。然而，目前还不清楚星系是如何在这个框架内形成和演化的，而了解这个过程是如何发生的是当今宇宙学的最大挑战之一。对我们周围星系的详细观察为了解形成其内部结构的过程提供了重要线索。类似于银河系的螺旋星系在这方面特别有用，因为它们的性质可以从其圆盘中气体和恒星的分布和轨道速度中推断出来。因此，对附近螺旋星系的详细结构研究提供了关键证据，使天文学家能够破译星系形成和演化的物理学。**旋涡星系的测量结构和简单的理论预测之间的早期比较发现，两者存在很大的差异。天文学家现在怀疑，这种分歧并不是因为宇宙学的失败，而是因为忽视了星系形成的细节。现在很清楚，气体和恒星在星系形成期间改变暗物质晕的效率比之前认为的更高，而且不同星系组件形成后微妙的相互作用也可以推动星系演化。**虽然已经引用了几种看似合理的机制来解释附近星系的观测结构，但尚不清楚哪些机制在星系形成过程中是通用的。详细的宇宙学模拟和少数几个观测到的星系之间的概念验证比较已经取得了成功，但整个星系群体的研究仍然缺乏。这在一定程度上是由于缺乏高质量的附近星系的轨道速度图，需要这些仔细的比较。在不久的将来，随着不同波长的大型光谱测量的出现，这种情况将会改变。同时，现代望远镜的大小和效率使得对单个星系的细致研究成为可能。因此，未来几年对星系形成研究来说是令人兴奋的几年，因为首次有可能对提出的理论进行系统测试。**我研究的主要目的是在宇宙学的背景下了解附近螺旋星系的结构。我的研究小组使用我们为此开发的软件对大银河系样本进行系统的结构研究。我们的代码的物理性和健壮性是无与伦比的，因此我们的团队准备从即将到来的调查中限制附近数千个螺旋星系的暗物质和发光物质的含量。我的团队还设计并进行了关于局部宇宙中极端或独特系统的新颖实验，以便洞察整个银河系群体的物理学。我的项目提供了一个协作的、世界级的培训环境，高素质的人才在其中脱颖而出。**加拿大在天文学领域处于国际领先地位，在该领域经常排名第一：这种成功带来了技术和创新，使我们的国家在世界舞台上具有竞争优势。我的计划解决了一些推动天文学研究的关键问题：当暗物质晕中形成螺旋星系时，它们是如何改变的？螺旋星系中恒星和气体的轨道如何驱动它们的演化？当考虑到这些过程时，观察到的螺旋星系的结构是否与宇宙学预测一致？暗物质的性质是什么？我的工作将有助于回答这些问题，朝着我所在领域的最终目标--发展一套完整的宇宙星系形成和演化理论--取得进展。