Stellar kinematics in the solar neighbourhood
O. Bienayme
Our understanding of the kinematics and galactic structure has been
drastically improved with new large photometric, astrometric and
spectroscopic surveys. For instance the description of the galactic
disc at low and very low galactic latitudes has been clarified thanks
to the global extinction map deduced from 2mass counts by Robin et al
(2009), giving detailed and global descriptions of warps and flare. The
inner galactic bars, bulge and arms are partly disentangled thanks to
the Spitzer/GLIMPSE survey (Churchwell et al 2009), and well defined
spiral arms out to 25 kpc are seen from a new analysis of HI surveys
(Levine et al 2006).
Many structures have been discovered at all scales within our Galaxy,
the Monoceros ring in the outer disk, thin streams but also massive
overdensity and strong asymmetry in deep star counts... Our Galaxy does
not look anymore as smooth as it was supposed, but can be certainly
compared to the perturbed M31-M33 interacting system.
The large kinematics RAVE and SEGUE surveys give new precise
constraints on the Galaxy mass (Smith et al 2008) and the nearly
spherical shape of the inner potential of the Galaxy (Siebert et al
2008) while Carollo et al (2009) show without ambiguity that the disks
and halo stars populate two separated regions in the orbit
eccentricity--[Fe/H] diagram and that they are two strictly separated
populations.