Issue |
A&A
Volume 569, September 2014
|
|
---|---|---|
Article Number | A69 | |
Number of page(s) | 9 | |
Section | Galactic structure, stellar clusters and populations | |
DOI | https://doi.org/10.1051/0004-6361/201423666 | |
Published online | 25 September 2014 |
The Galactic bar and the large scale velocity gradients in the Galactic disk
1
Kapteyn Astronomical Institute,
Rijksuniversiteit Groningen, PO Box
800
9700 AV
Groningen
The Netherlands
e-mail:
monari@astro.rug.nl
2
ESA, European Space Research and Technology Center (ESTEC),
Keplerlaan 1, 2201
AZ
Noordwijk, The
Netherlands
3
Leibniz-Institut für Astrophysik Potsdam (AIP),
An der Sternwarte
16, 14482
Potsdam,
Germany
Received:
18
February
2014
Accepted:
28
July
2014
We investigate whether the cylindrical (galactocentric) radial velocity gradient of ~ −3 km s-1 kpc-1, directed radially from the Galactic center and recently observed in the stars of the solar neighborhood with the RAVE survey, can be explained by the resonant effects of the bar near the solar neighborhood. We compared the results of test particle simulations of the Milky Way with a potential that includes a rotating bar with observations from the RAVE survey. To this end we applied the RAVE selection function to the simulations and convolved these with the characteristic RAVE errors. We explored different “solar neighborhoods” in the simulations, as well as different bar models. We find that the bar induces a negative radial velocity gradient at every height from the Galactic plane, outside the outer Lindblad resonance and for angles from the long axis of the bar compatible with the current estimates. The selection function and errors do not wash away the gradient, but often make it steeper, especially near the Galactic plane, because this is where the RAVE survey is less radially extended. No gradient in the vertical velocity is present in our simulations, from which we may conclude that this cannot be induced by the bar.
Key words: Galaxy: kinematics and dynamics / solar neighborhood / Galaxy: structure / Galaxy: evolution
© ESO, 2014
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