Stellar Stream Candidates in the Solar Neighborhood Found in the LAMOST DR3 and TGAS

TL;DR

This study identifies 16 stellar stream candidates in the solar neighborhood by analyzing combined LAMOST DR3 and Gaia TGAS data, revealing new and known kinematic groups and their potential origins.

Contribution

It introduces a wavelet transform-based method to detect stellar streams in combined spectroscopic and astrometric data, discovering four new candidates.

Findings

Identified 16 stellar overdensities with similar kinematics.

Discovered four new stellar stream candidates.

Observed clear kinematic gaps and shifts in velocity space.

Abstract

We have cross-matched the LAMOST DR3 with the Gaia DR1 TGAS catalogs and obtained a sample of 166,827 stars with reliable kinematics. A technique based on the wavelet transform was applied to detect significant overdensities in velocity space among five subsamples divided by spatial position. In total, 16 significant overdensities of stars with very similar kinematics were identified. Among these, four are new stream candidates and the rest are previously known groups. Both the U-V velocity and metallicity distributions of the local sample show a clear gap between the Hercules structure and the Hyades-Pleiades structure. The U-V positions of these peaks shift with the spatial position. Following a description of our analysis, we speculate on possible origins of our stream candidates.