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Physics & Astronomy Colloquium – Fall 2018 – Bershady
September 5 @ 3:30 pm - 5:00 pm
Speaker: Matthew Bershady (University of Wisconsin)
Title: Galaxy Disks in Phase Space
Abstract: Rotating disks of stars in galaxies have a thickness in which there
are age and abundance gradients. Understanding this vertical structure
is a linchpin for inferring the present-day mass and formation
history of disks. We explain how what amounts to a stellar phase-space
stratification may arise from settling of decreasingly turbulent gas
(cooling) or dynamical heating from scattering. We show how the
stratification and its rate can be measured in the nearby, edge-on
galaxy NGC 891, and then how the measurement can be extended to large
samples of nearby galaxies from the Sloan Digitial Sky
Survey-IV. These advances leverage a unique archaeological record that
tell us how galaxy disks have assembled.
Bio: Matthew Bershady is a Professor in the Department of Astronomy and
Ciriacks Faculty Fellow in the College of Letters & Science at the
University of Wisconsin-Madison, where he currently serves as Project
Scientist for the Sloan Digital Sky Survey-IV.