A spectroscopic survey of thick disc stars outside the solar neighbourhood

Details A spectroscopic survey of thick disc stars outside the solar neighbourhood A spectroscopic survey of thick disc stars outside the solar neighbourhood

2011-10-24

arxiv.org/abs/1110.5221v1

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

19 pages, 15 figures, accepted for publication in A&A

Scientific paper

We performed a spectroscopic survey of nearly 700 stars probing the galactic thick disc far from the solar neighbourhood towards the galactic coordinates (l~277, b~47). The derived effective temperatures, surface gravities and overall metallicities were then combined with stellar evolution isochrones, radial velocities and proper motions to derive the distances, kinematics and orbital parameters of the sample stars. The targets belonging to each galactic component (thin disc, thick disc, halo) were selected either on their kinematics or according to their position above the galactic plane, and the vertical gradients were also estimated. We present here atmospheric parameters, distances and kinematics for this sample, and a comparison of our kinematic and metallicity distributions with the Besancon model of the Milky Way. The thick disc far from the solar neighbourhood is found to differ only slightly from the thick disc properties as derived in the solar vicinity. For regions where the thick disc dominates, we measured vertical velocity and metallicity trends of d(V_phi)/dZ = 19 +/- 8 km/s/kpc and d[M/H]/dZ = -0.14 +/- 0.05 dex/kpc, respectively. These trends can be explained as a smooth transition between the different galactic components, although intrinsic gradients could not be excluded. In addition, a correlation d(V_phi)/d[M/H] = -45 +/- 12 km/s/dex between the orbital velocity and the metallicity of the thick disc is detected. This gradient is inconsistent with the SDSS photometric survey analysis, which did not detect any such trend, and challenges radial migration models of thick disc formation. Estimations of the scale heights and scale lengths for different metallicity bins of the thick disc result in consistent values, with hR~3.4 \pm 0.7 kpc, and hZ~694 \pm 45 pc, showing no evidence of relics of destroyed massive satellites.

Affiliated with

Also associated with

No associations

Rating

A spectroscopic survey of thick disc stars outside the solar neighbourhood does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A spectroscopic survey of thick disc stars outside the solar neighbourhood, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A spectroscopic survey of thick disc stars outside the solar neighbourhood will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-520613