Comparison of the simulated mergers with observed FS CMa stars. Left panel: W component of the space velocity. Due to the low number of extremely fast FS CMa stars, the displayed range of velocities is restricted from −20 to −2 km/s and 2 to 20 km/s (the full distribution is shown in Fig. A.1). The region around a zero value for the W velocity has also been removed. Even if the majority of simulated mergers occupies this region, it is impossible to compare them with observations due to high extinction in the galactic plane. Right panel: same sample of mergers, plotted in space velocity with respect to the galactic centre.