Le 31 janvier 2014
De 10h30 à 12h00
Giacomo MONARI
Kapteyn Instituut, Rijksuniversiteit Groningen
The study of kinematic groups of stars and streaming motions in the Solar Neighborhood has a long tradition. The interest on the subject has been amplified in modern times after the results of Hipparcos data and other surveys, and in the future we expect, with Gaia, a revolution in our understanding of the Milky Way. The moving groups in the thin disk have been often associated with the disruption of open clusters or with the dynamical effects of the non-axisymmetric components of the Milky Way (bar, spiral arms). However, when we speak about kinematical substructure in the thick disk, we usually think of the remnants of some accretion events. With the help of 3D test particle simulations of the Milky Way, I will show for the first time that the bar modifies significantly the velocity distribution both of thin and thick disk. I will also show how the bar can induce negative velocity gradients in the extended Solar Neighborhood, even high from the Galactic plane, similarly to what is observed in the RAVE survey. Finally, I will present some preliminary results of our study on the orbital structure induced by the bar, that we carry out with the help of the spectral analysis of orbital frequencies.