Radial migration in disc galaxies — I. Transient spiral structure and dynamics

We seek to understand the origin of radial migration in spiral galaxies by analysing in detail the structure and evolution of an idealized, isolated galactic disc. To understand the redistribution of stars, we characterize the time evolution of properties of spirals that spontaneously form in the disc. Our models unambiguously show that in such discs, single spirals are unlikely, but that a number of transient patterns may coexist in the disc. …