Events at Physics
Events on Thursday, March 4th, 2021
- Graduate Program Event
- PhD Prospective Student VIRTUAL Visit Day
- Time: 12:00 am
- Place: Virtual
- Speaker: PhD Program Faculty & Graduate Students, UW-Madison, Department of Physics
- Abstract: All admitted Ph.D. students for Fall 2021 will be invited for prospective student virtual visit days. Graduate students and faculty will receive more information as the dates approach.
- Host: Michelle Holland, Graduate Program Coordinator
- Astronomy Colloquium
- What Sets the Efficiency of Radial Migration is Spiral Galaxies?
- Time: 3:30 pm
- Place: Zoom meeting(see Abstract ) Coffee and tea 3:30pm, Talk 3:45pm
- Speaker: Kate Daniels, Bryn Mawr
- Abstract: After an initial epoch of assembly, spiral galaxies like the Milky Way evolve primarily under the influence of slow, internal processes. This secular evolution rearranges the orbital angular momentum and energy of a galaxy’s disk, thus altering its kinematics, morphology, and chemical distribution. Central to our understanding of secular evolution is how transient spiral arms cause stars to migrate large radial distances from their birth radii. Radial migration is often associated with increased orbital eccentricity, thus kinematically heating the disk. However, a particularly important type of radial migration, called churning or cold torquing, can change the sizes of stellar orbits in the disk without significantly altering their eccentricities. The relative importance of cold or heating radial migration significantly impacts how disks evolve. In this talk, I will demystify the physics that governs various forms of radial migration and discuss their observational signatures. I will then present scaling relations for the efficiency of cold torquing. Finally, I will argue that in some limits cold torquing can, in fact, kinematically heat the disk. First steps have been taken, but there is an ongoing need to further develop this theoretical framework for the interpretation of data from high resolution simulations and large, high precision observational surveys of the Milky Way.
- Host: Melinda Soares-Furtado