Gaia Data Release 2. Mapping the Milky Way disc kinematics

0495336 - ASÚ 2019 RIV FR eng J - Journal Article
Katz, D. - Antoja, T. - Romero-Gomez, M. - Drimmel, R. - Reyle, C. - Seabroke, G.M. - Soubiran, C. - Babusiaux, C. - Di Matteo, L. - Koubský, Pavel - Votruba, Viktor … Total 452 authors
Gaia Data Release 2. Mapping the Milky Way disc kinematics.
Astronomy & Astrophysics. Roč. 616, August (2018), č. článku A11. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA MŠMT(CZ) LG15010
Institutional support: RVO:67985815
Keywords : galaxy * kinematics and dynamics * disk
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.209, year: 2018

Gaia DR2 allows us to draw 3D maps of the Galactocentric median velocities and velocity dispersions with unprecedented accuracy, precision, and spatial resolution. The maps show the complexity and richness of the velocity field of the galactic disc. We observe streaming motions in all the components of the velocities as well as patterns in the velocity dispersions. For example, we confirm the previously reported negative and positive galactocentric radial velocity gradients in the inner and outer disc, respectively. Here, we see them as part of a non-axisymmetric kinematic oscillation, and we map its azimuthal and vertical behaviour. We also witness a new global arrangement of stars in the velocity plane of the solar neighbourhood and in distant regions in which stars are organised in thin substructures with the shape of circular arches that are oriented approximately along the horizontal direction in the U - V plane. Moreover, in distant regions, we see variations in the velocity substructures more clearly than ever before, in particular, variations in the velocity of the Hercules stream.
Permanent Link: http://hdl.handle.net/11104/0288339