Modelling the gaseous disk of the milky way galaxy

这是一项关于培养射电天文学研究生的建议。他们将参加用世界上最大的望远镜观测的新一代大规模射电测量，并发现星际空间的新现象。一个在射电天文学方面拥有坚实基础的社区对于加拿大保持在星际中天体物理学的前沿是必要的，这是我们在正在进行的国际射电天空测量中的领先地位。这项提议概述了一个研究计划，该计划将重振这个基本上在30年前处于休眠状态的领域，并在理解我们的祖国银河系的结构方面取得新的进展。射电望远镜显示，氢原子气体充满了我们银河系家园的体积。这种气体分布广泛，是绘制银河系螺旋结构和运动的极好工具，因为它以流体般的一致性对兆瓦恒星群的引力场做出响应。然而，了解我们的银河系从远处看到底是什么样子，就像被要求绘制一整片森林的地图一样，当它被绑在边界内的一棵树上时。为了解决将银河系可视化的挑战，我提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”，包括已知存在于银河系中的特征，被构建起来，并在计算机中用模拟射电望远镜进行“观测”。然后将这些模型观测与真实观测进行比较，组成模型星系的数值参数是不同的，直到真实数据得到最好的再现。有了这些“贴合”的模型，我们可以跟踪银河系的自转，并制作出银河系旋臂的新视觉地图，给我们一个准确的银河系气体结构和动力学的“全景图”。所提出的建模方法最终将给我们提供迄今为止最好的银河系鸟瞰，并将促进我们对存在于恒星之间的宇宙气体以及这两个群体之间的相互作用的理解。

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.