Velocity distribution of the local (< 1 kpc) stellar halo using Gaia data (large panel) and in the Villalobos & Helmi (2008) simulations, where the small panels indicate the orbital inclination (0°, 30° or, 60°) and whether the merger was prograde or retrograde. Stellar particles from the discy (spherical) satellites are shown in blue (red). The distinct velocity distributions of these stars betray the progenitor’s properties and the merger geometry.