Effective Jeans diameter () versus filamentintrinsic central column density. The vertical dashed line and the grey band mark the border zone between subcritical and supercritical filaments (cf. Fig. 6). The dotted line running from the top left to the bottom right corresponds to the thermal Jeans diameter (2R_J). The blue solid lines correspond to the best fits for the subcritical () and supercritical () filament subsamples, respectively. The exponent of the power-law fit for the supercritical filaments becomes  −0.4 ± 0.1 after excluding DR21 and NGC 2264C from the sample. In contrast to the thermal Jeans length, the effective Jeans diameter of the supercritical filaments remains roughly constant with an average value of 0.14 ± 0.07 pc.