Grant: Discovery Grants Program - Individual

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.