Siebert, A;
Famaey, B;
Minchev, I;
Seabroke, GM;
Binney, J;
Burnett, B;
Freeman, KC;
... Zwitter, T; + view all
(2011)
Detection of a radial velocity gradient in the extended local disc with RAVE.
Monthly Notices of the Royal Astronomical Society
, 412
(3)
pp. 2026-2032.
10.1111/j.1365-2966.2010.18037.x.
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Abstract
Using a sample of 213 713 stars from the Radial Velocity Experiment (RAVE) survey, limited to a distance of 2 kpc from the Sun and to |z| < 1 kpc, we report the detection of a velocity gradient of disc stars in the fourth quadrant, directed radially from the Galactic Centre. In the direction of the Galactic Centre, we apply a simple method independent of stellar proper motions and of Galactic parameters to assess the existence of this gradient in the RAVE data. This velocity gradient corresponds to |K+C| > rsim 3 km s−1 kpc−1, where K and C are the Oort constants measuring the local divergence and radial shear of the velocity field, respectively. In order to illustrate the effect, assuming a zero radial velocity of the local standard of rest we then reconstruct the two-dimensional Galactocentric velocity maps using two different sets of proper motions and photometric distances based either on isochrone fitting or on K-band magnitudes, and considering two sets of values for the Galactocentric radius of the Sun and local circular speed. Further observational confirmation of our finding with line-of-sight velocities of stars at low latitudes, together with further modelling, should help constrain the non-axisymmetric components of the Galactic potential, including the bar, the spiral arms and possibly the ellipticity of the dark halo.
| Type: | Article |
|---|---|
| Title: | Detection of a radial velocity gradient in the extended local disc with RAVE |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1111/j.1365-2966.2010.18037.x |
| Publisher version: | https://doi.org/10.1111/j.1365-2966.2010.18037.x |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | stars: kinematics and dynamics, Galaxy: fundamental parameters, Galaxy: kinematics and dynamics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10090699 |
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