Top: RV distribution of the full sample of cluster members observed by GES. The red and green dashed lines describe the best-fit models with a Gaussian broadened by the measurement errors and the velocity offsets due to binaries, assuming a fixed binary fraction (f_bin = 0.5) and leaving the binary fraction free to vary, respectively. Bottom: distribution of the RVs of the pre-stellar cores measured by Tsitali et al. (2015) from the C¹⁸O (2−1) molecular transition, with the best-fit models with a Gaussian function superimposed.