English

The imprints of the Galactic bar on the thick disk with RAVE

Astrophysics of Galaxies 2015-06-24 v1

Abstract

We study the kinematics of a local sample of stars, located within a cylinder of 500 pc radius centered on the Sun, in the RAVE dataset. We find clear asymmetries in the vRv_R-vϕv_\phi velocity distributions of thin and thick disk stars: here are more stars moving radially outwards for low azimuthal velocities and more radially inwards for high azimuthal velocities. Such asymmetries have been previously reported for the thin disk as being due to the Galactic bar, but this is the first time that the same type of structures are seen in the thick disk. Our findings imply that the velocities of thick disk stars should no longer be described by Schwarzschild's, multivariate Gaussian or purely axisymmetric distributions. Furthermore, the nature of previously reported substructures in the thick disk needs to be revisited as these could be associated with dynamical resonances rather than to accretion events. It is clear that dynamical models of the Galaxy must fit the 3D velocity distributions of the disks, rather than the projected 1D, if we are to understand the Galaxy fully.

Keywords

Cite

@article{arxiv.1503.02072,
  title  = {The imprints of the Galactic bar on the thick disk with RAVE},
  author = {T. Antoja and G. Monari and A. Helmi and O. Bienaymé and J. Bland-Hawthorn and B. Famaey and B. K. Gibson and E. K. Grebel and G. Kordopatis and U. Munari and J. Navarro and Q. Parker and W. A. Reid and G. Seabroke and M. Steinmetz and T. Zwitter},
  journal= {arXiv preprint arXiv:1503.02072},
  year   = {2015}
}

Comments

Accepted for publication in ApJL; 7 pages, 3 figures, 1 table