18 février 2020Mixing processes in disk galaxies

Paola DI MATTEO
Observatoire de Paris

Galaxy structures form and evolve through a variety of physical processes which induce angular momentum exchange and redistribution of stellar orbits. As a consequence, stars may be found in regions different from those where they were born. This redistribution and mixing of stars must be taken into account when interpreting the properties of stellar populations, dispersions in age- metallicity relations, structural and kinematic characteristics of the different galactic components. In this talk, I will discuss some examples of mixing and redistribution of stars in disk galaxies : (i) Stellar migration induced by secular evolution and its impact on the properties of boxy bulges; (ii) The role of minor mergers in the formation of the inner halo of galaxies by ‘heating“^o of a pre-existing thin disk; (iii) Stellar streams in the galactic halo, presenting some recent results about the streams associated to the galactic globular cluster Palomar 5 and their relationship with the lumpiness of the dark matter halo.