Astrophysics Seminar: Xinlun Cheng, University of Virginia


Location: 184 Nieuwland Science Hall (View on map )

Revisiting the Dynamics of the Disk in the Age of Gaia and APOGEE

Xinlun Cheng
Graduate Student
University of Virginia

In the age of large sky surveys, such as Gaia and APOGEE, astronomers enjoy larger datasets with incredible precision, and they have revolutionized our understanding of the Milky Way galaxy. I will focus on two examples of how these advances have changed our view of the Milky way's disk: measuring the surface mass density of the disk (i.e., the classical ‘Kz Problem’) and our understanding of the Galactic warp. In the Kz problem, we discover that we have reached the limit of traditional analytical treatment that has been in use for almost a century, finding multiple assumptions made that no longer hold true. We conclude that to move forward on this problem, more complex models of the Galaxy are necessary. I will also talk about how new data has revolutionized our understanding of the Galactic warp, a phenomenon first discovered in the Milky Way in the early 2000s. We discovered a decrease in vertical velocity in the outer disk for the first time, a strong indication of a precessing warp, and we will also briefly touch on the evolution of the dynamics of the warp.

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