SIMBAD references

We use ESA/Gaia astrometry together with SEGUE and LAMOST measurements of the GD-1 stellar stream to explore the improvement on the Galactic gravitational potential that these new data provide. Assuming a realistic universal model for the dark matter halo together with reasonable models of the baryonic components, we find that the orbital solutions for GD-1 require the circular velocity at the Solar radius to be V_ circ_( R_☉)=244±_4 km s^–1, and also that the density flattening of the dark halo is q_ρ=0.82^+0.25_–0.13. The corresponding Galactic mass within 20 kpc was estimated to be M_ MW_(< 20 kpc)=2.5±0.2 ×10¹¹ M_☉_. Moreover, Gaia's excellent proper motions also allowed us to constrain the velocity dispersion of the GD-1 stream in the direction tangential to the line of sight to be < 2.30 km s^–1 (95 per cent confidence limit), confirming the extremely cold dynamical nature of this system.