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

T. Antoja, G. Monari, A. Helmi, O. Bienaymé, J. Bland-Hawthorn, B. Famaey, B. K. Gibson, E. K. Grebel, G. Kordopatis, U. Munari, J. Navarro, Q. Parker, W. A. Reid, G. Seabroke, M. Steinmetz, T. Zwitter

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13 Citations (Scopus)
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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 data set. We find clear asymmetries in the vR v∞ velocity distributions of thin and thick disk stars: there are more stars moving radially outward for low azimuthal velocities and more radially inward 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 Schwarzschilds, 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.

Original languageEnglish
Article numberL32
Pages (from-to)1-7
Number of pages7
JournalAstrophysical Journal Letters
Volume800
Issue number2
DOIs
Publication statusPublished - 20 Feb 2015

Bibliographical note

Copyright 2015 The American Astronomical Society. Firstly published in the Astrophysical Journal Letters, 800(2), L32, 2015, published by IOP Publishing. The original publication is available at http://www.doi.org/10.1088/2041-8205/800/2/L32. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

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