Member stars of the GD1 tidal stream from the SDSS, LAMOST and Gaia surveys

TL;DR

This study identifies 71 probable GD-1 stream stars using SDSS, LAMOST, and Gaia data, providing detailed position-velocity maps and metallicity measurements to inform models of the Milky Way's mass distribution.

Contribution

It presents a comprehensive catalog of GD-1 stream members with precise spectroscopic and astrometric data, enabling improved modeling of the stream's origin and the Galaxy's gravitational potential.

Findings

71 probable GD-1 stream members identified

Stream's average metallicity [Fe/H] = -1.95 ± 0.23

Detailed position-velocity diagrams constructed

Abstract

With the photometric data from the SDSS survey, the spectroscopic data from the SDSS/SEGUE and the LAMOST surveys, and the astrometric data from the Gaia DR2, we have identified 71 highly-probable member stars of the GD-1 cold stellar stream spread along almost its entire length (i.e. from 126 to 203 degree in Right Ascension). With the accurate spectroscopic (i.e. metallicity and line-of-sight velocity) and astrometric (i.e. proper motions) information, the position-velocity diagrams, i.e. $\phi_{1}$-$\mu_{\alpha}$, $\phi_{1}$-$\mu_{\delta}$ and $\phi_{1}$-${v_{\rm gsr}}$, of the GD-1 stream are well mapped. The stream has an average metallicity [Fe/H] $= -1.95 \pm 0.23$. The rich information of member stars of the stream now available allow one not only to model its origin, but also to place strong constraints on the mass distribution and the gravitational potential of the Milky Way.