Position-velocity plot of GC late-type stars along Galactic longitude, centred on Sgr A^★. Each diamond symbol denotes a star, and green x-symbols denote stars that we consider high-velocity stars. The red line denotes the moving average V_LOS of 150 stars, the blue lines denote the moving robust σ_r × 2.5, which is close to our cuts to classify high-velocity stars, shown as dashed horizontal lines.