Submitting Campus

Daytona Beach


Physical Sciences

Document Type


Publication/Presentation Date



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 7993 F, G, and K nearby main-sequence stars (d < 2 kpc) with estimates of position (x, y, z) and space velocity (U, V, W) based on color and proper motion from the Sloan Digital Sky Survey DR9 catalog. Three “phase-space overdensities” are identified in (V,√U2 + 2V 2) with significance levels of σ > 3. Two of them (the Hyades–Pleiades stream and the Arcturus–AF06 stream) have been identified previously. We also find evidence for a new stream (centered at V ∼ −180 km s−1) in the halo. The formation mechanisms of these three streams are analyzed. Our results support the hypothesis that the Arcturus–AF06 stream and the new stream originated from the debris of a disrupted satellite, while the Hyades–Pleiades stream has a dynamical origin.

Publication Title

The Astrophysical Journal



IOP Publishing

Grant or Award Name

National Natural Science Foundation of China grant Nos. 11390371, 11233004, 11222326, and 11103034, National Key Basic Research Program of China (973 program) 2014CB845701 and 2014CB845703, U.S. National Science Foundation (AST-1358787)