Left: Herschel column-density map of the Ophiuchus molecular cloud at an effective HPBW resolution of 18.2′′. The column-density map is given in units of H₂ cm⁻², calculated on a pixel-by-pixel basis using a multi-scale graybody fitting procedure (see Appendix A of Palmeirim et al. 2013). Right: same as the left panel with the candidate prestellar cores identified in Sect. 4.4 overlaid as green triangles and the unbound starless cores as orange triangles. The bar at the lower right indicates a scale of 2 pc.