Kinematics of the Galactic disk from LAMOST Dwarf sample

Abstract

Based on the LAMOST survey and Sloan Digital Sky Survey (SDSS), we use low-resolution spectra of 130,043 F/G-type dwarf stars to study the kinematics and metallicity properties of the Galactic disk. Our study shows that the stars with poorer metallicity and larger vertical distance from Galactic plane tend to have larger eccentricity and velocity dispersion. After separating the sample stars into likely thin-disk and thick-disk sub-sample, we find that there exits a negative gradient of rotation velocity $V_{\varphi }$ with metallicity [Fe/H] for the likely thin-disk sub-sample, and the thick-disk sub-sample exhibit a larger positive gradient of rotation velocity with metallicity. By comparing with model prediction, we consider the radial migration of stars appears to have influenced on the thin-disk formation. In addition, our results shows that the observed thick-disk stellar orbital eccentricity distribution peaks at low eccentricity ($e\sim 0.2$) and extends to a high eccentricity ($e\sim 0.8$). We compare this result with four thick-disk formation simulated models, and it imply that our result is consistent with gas-rich merger model.

9 pages, 11 figures, Accepted for publication in MNRAS. arXiv admin note: text overlap with arXiv:1104.3114 by other authors

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Cited by in corpus (5)

• Kinematics of the local disk from the RAVE survey and the Gaia first data release
• Age-metallicity dependent stellar kinematics of the Milky Way disc from LAMOST and Gaia
• Insights into the Formation and Evolution History of the Galactic Disk System
• Vertical structure of Galactic disk kinematics from LAMOST K giants
• Existence of the Metal-Rich Stellar Halo and High-velocity Thick Disk in the Galaxy