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Milky Way models in the Gaia era: shaping stellar populations in phase-space and their chemical composition

Le 8 février 2019
De 10h30 à 12h00

Sergey Khoperskov (MPE)


I will discuss the formation history of the stellar components in the Milky Way-type galaxies based on self-consistent chemodynamical galaxy formation models. Our hydrodynamical/N-body simulations initially form compact and kinematically hot disks through the high star formation regime in a turbulent thick gaseous disk. Further, during the quiescent star formation phase models reproduce thinner (and colder) disk components. These our models predict an apparent bimodality in the [Fe/H]-[\alpha/Fe] plane. [\alpha/Fe] ratios correlate with age, such that \alpha-rich stars are older, however, the dispersion of [\alpha/Fe] abundances for a given age (or metallicity) is not negligible and depends mainly on the star formation efficiency. In order to explore the origin of the Milky Way disk chemical structure and match our models with the spectroscopic surveys we discuss the effects of the gas infall rate, initial gas fraction, the cooling time and morphological transformation of galaxies on the resulting shape of [Fe/H]-[\alpha/Fe] as a function of stellar age and position in the disk. In the self-consistent galaxy formation models, I discuss the origin of chemical peculiarities of the phase-space substructures in the disc of the Milky Way, such as the ridges in the plane 'r - Vphi', the undulations in the space 'Vphi-r-Vr'. I also present some new results on the interpretation of phase-space spirals recently discovered in Gaia DR2.

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