Modelling the gaseous disk of the milky way galaxy

这是一项培养射电天文学研究生的建议。他们将参与新一代的大型射电观测，用世界上最大的望远镜观测，发现星际空间的新现象。一个在射电天文学方面有着坚实基础的社区对于加拿大保持在星际介质天体物理学的前沿是必要的，这是我们在正在进行的国际无线电天空调查中的领导地位。这一提议概述了一项研究计划，该计划重振了一个在三十年前基本上处于休眠状态的领域，并开拓了了解我们的家园银河系结构的新进展。射电望远镜显示，氢原子充满了我们银河系的体积。这种气体分布广泛，是绘制银河系螺旋结构和运动的绝佳工具，因为它以流体般的一致性对MW恒星群的引力场做出反应。然而，从远处了解我们银河系的实际面貌就像是被要求绘制整个森林的地图，而森林却与其边界内的一棵树联系在一起。为了应对银河系可视化的挑战，我建议对氢原子的射电观测进行定量建模。一个星系的数学“模型”，包括银河系中已知存在的特征，在计算机中用模拟射电望远镜构建和“观察”。然后将这些模型观测结果与真实的观测结果进行比较，并改变构成模型星系的数值参数，直到最好地再现真实的数据。有了这些“拟合”的模型，我们可以追踪银河系的旋转，并绘制银河系旋臂的新的视觉地图，为我们提供银河系气体结构和动力学的准确“大图”。所提出的建模方法最终将为我们提供迄今为止最好的银河系鸟瞰图，并将促进我们对恒星之间存在的宇宙气体的理解，以及这两个群体之间的相互作用。

This is a proposal to train graduate students in radio astronomy. They will participate in a new generation of large-scale radio surveys observed with the world's largest telescopes, and make discoveries of new phenomena in interstellar space. A community with a strong foundation in radio astronomy is necessary for Canada to remain at the forefront of interstellar medium astrophysics, a position we hold with our leadership in ongoing international radio surveys of the sky.This proposal outlines a research program that reinvigorates a field that essentially became dormant three decades ago, and pioneers new inroads into understanding the structure of our home galaxy, the Milky Way. Radio telescopes reveal that atomic hydrogen gas fills the volume of our galactic home. This gas is widespread and an excellent tool for mapping spiral structure and motions in the Galaxy, as it responds with fluid-like consistency to the gravitational field of the MW's population of stars. However, understanding what our Galaxy actually looks like from afar is akin to being asked to map an entire forest when tied to a single tree within its boundaries. To tackle the challenge of visualizing the Milky Way, I propose to quantitatively model radio observations of atomic hydrogen. A mathematical "model" of a galaxy, complete with features known to exist in the Milky Way, is constructed and "observed" in the computer with a simulated radio telescope. These model observations are then compared to real ones, and numerical parameters that make up the model galaxy are varied until the real data are best reproduced. With these "fitted" models, we can trace our Galaxy's rotation, and make new visual maps of our Galaxy's spiral arms, giving us an accurate "big-picture" of the Milky Way's gaseous structure and dynamics.The modelling approach proposed will ultimately give us the best birds-eye view of our Galaxy yet, and will advance our understanding of the cosmic gas that exists between the stars, and the interplay between these two populations.