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تسجيل مستخدم جديدThree Moving Groups Detected in the LAMOST DR1 Archive
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We analyze the kinematics of thick disk and halo stars observed by the Large sky Area Multi-Object Fiber Spectroscopic Telescope. We have constructed a sample of 7,993 F, G and K nearby main-sequence stars (textit{d} $<$ 2 kpc) with estimates of position (x, y, z) and space velocity ($U$, $V$, $W$) based on color and proper motion from the SDSS DR9 catalog. Three `phase-space overdensities are identified in [textit{V}, $sqrt{U^{2}+2V^{2}}$] with significance levels of $sigma$ $>$ 3. %[L$_{Z}$, eccentricity], [L$_{Z}$, L$_{bot}$], and [V$_{az}$, V$_{triangle}E$]. Two of them (Hyades-Pleiades stream, Arcturus-AF06 stream) have been identified previously. We also find evidence for a new stream (centered at textit{V} $sim$ -180 km s$^{-1}$) in the halo. The formation mechanisms of these three streams are analyzed. Our results support the hypothesis the Arcturus-AF06 stream and the new stream originated from the debris of a disrupted satellite, while Hyades-Pleiades stream has a dynamical origin.
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