Francois Mernier

I will discuss the cosmological origin of stellar and gaseous disks in the Milky Way (MW) and similar-mass galaxies, using the FIRE (Feedback in Realistic Environments) cosmological zoom-in simulations. First, I will discuss the formation history of the MW, addressing when the main progenitor of the MW likely formed and how this depends on the Local Group environment. Then, I will discuss how stellar and gaseous disks dynamically settle over cosmic time, and how stars are dynamically heated within the disk after they form. I will compare the relative importance of disk setting and post-formation dynamical heating for determining the observable relation between stellar kinematics and stellar age today. I will show how these effects lead to thin+thick stellar disk morphology, as observed in the MW and nearby galaxies. Finally, I will discuss the origin, evolution, and relative importance of 3D spatial variations of metallicity in stellar and gas, including radial and vertical gradients, and how these elemental abundance patterns relate to the evolution of disk dynamics and star formation within a galaxy.