Left panel: comparison of robust bound cores and starless cores. Histograms with the y-axis on the left show the distributions of all starless cores (blue) and all bound cores (green). The red and black lines (right y-axis) show cumulative surface density distributions for all bound cores and the off-filament bound cores, respectively. These distributions were derived by dividing the number of cores found at a certain N(H₂) level by the total area in the image where the density is below that value. Right panel: prestellar core mass vs. background N(H₂). Triangles are the mean mass averaged over bins of 10²¹ cm⁻². The linear fit is shown as a red line.