Fitting the Secular Evolution of the Milky Way Disk
Abstract
Disk galaxies present a great regularity in their stellar bodies but
reveal complex structures in their young stars and gas. The Milky Way is
an ideal model organism to study the connection between the highly
structured birth conditions and the subsequent dynamical evolution of
its disk, as 6D phase space information was collected by the
spectroscopic survey SDSS and Gaia space mission for its individual
stars. I will present a simple statistical model for the formation and
evolution of the Milky Way disk, describing when and where its stars
were born, with what metallicity, and how their orbits subsequently
evolved. The best fit model implies extensive radial migration, but only
modest orbital heating. Consequently, the disk looks regular without
losing its radial gradients. To address the possible drivers of this
long-term evolution, I will then open the discussion to the next steps
such modelling could take, drawing inspiration from cosmological
simulations.