Mass distribution of robust prestellar cores (blue), candidate prestellar cores (green), and unbound starless cores (red). The cyan area marks the difference between robust and candidate prestellar cores. To left of the vertical dashed line, the sample of prestellar cores is less than 80% complete according to Monte-Carlo simulations (see Sect. 4.6 and Appendix B). For comparison, the black dashed curve shows the system IMF (Chabrier 2005).