Astrophysics Colloquium--The Bones of the Milky Way (Speaker: Alyssa Goodman, Center for Astrophysics, Harvard)
Abstract: The Milky Way is typically thought of as a spiral galaxy, but our understanding of its detailed structure remains fuzzy thanks to our observational vantage point within its disk. Most of what we do know about the Milky Way's three-dimensional geometry comes from velocity-resolved observations of gas and stars. But, recently, it has become possible to combine exquisitely sensitive observations of dust with more traditional kinematically-resolved observations of gas to reveal totally new structures within the Milky Way. In this talk, I will explain why we now believe that some extraordinarily long and thin so-called "infrared dark clouds" are in fact "bones" of the Galaxy, centered within spiral arms, and, in at least one case, marking the geometric mid-plane the disk to within less than a few parsecs. The talk will highlight how both large surveys and new visualization tools have been critical in this investigation.