19) Chemo-kinematical facets of the Milky Way spiral arms and the bar resonances: relation to ridges and known moving groups

Abstract: By using superb Gaia Data Release 2 measurements of positions and velocities of stars complemented by chemical abundances delivered by APOGEE DR16, LAMOST DR5 and Galah DR2 spectroscopic surveys, we explore chemodynamical properties of the Milky Way spiral arms and constrain the location of the main resonances of the bar. Combining the data analysis with high-resolution N-body simulations we provide a consistent explanation of the large space patterns observed in the Galactic plane with the origin of moving groups in the local kinematic space of the Solar neighbourhood. We find that most of the kinematical arches in the vR-vφ plane are the parts of large-scale spiral arms of the Milky Way. Both the Outer Lindblad and corotation resonances are imprinted in the VR-vφ plane, as a part of the Hercules and the Sirius streams, respectively, which is further evidence of slowly rotating long bar. We find that the density gap above the corotation (Hercules streams in the VR-vφ-plane) has a lower metallicity than surrounding features and a sharp decrease of [Fe/H] behind the OLR-associated features. We demonstrate that the OLR limits the migration of metal-rich stars formed in the inner disk ([Fe/H] >0.2) beyond, as it is expected from simulations. The Arcturus stream contains very metal-rich stars ([Fe/H] >0.3) typical for the innermost part of the Milky Way which confirms its internal dynamical origin and its angular momentum distribution is close to the innermost Scutum-Sagittarius spiral arm of the Milky Way. On large galactic scales, the crossmatch of the Gaia DR 2 with the spectroscopic data allows us to discover the abundance variations across the spiral arms of the Milky Way disk. In particular, the amplitude of [Fe/H] variations of ~0.05 dex is visible along the large scale phase-space features associated with Local, Sagittarius and Perseus arms of the Milky Way. We discuss these results in the context of the spiral arms induced kinematical fractionality and ongoing radial migration in the Milky Way disk. In the talk we also extrapolate our findings for better understanding of the kinematics and structure of stellar populations in external Milky Way-type barred galaxies.

Bio:
- 2011-2013 PhD at the Institute of Astronomy (Moscow, Russia)
- 2014-2015, postdoc at University degli studi di Milano (Milan, Italy)
- 2016-2018, postdoc at Paris Observatory (Paris, France)
- 2018-2020, postdoc at Max Planck for Extraterrestrial Physics (Garching, Germany)
- 2020-present, postdoc at Leibniz-Institut für Astrophysik Potsdam, Germany