Probability density functions of the ¹³CO, HCO⁺, HCN, HNC, and N₂H⁺ column density for the whole filament. The dashed vertical lines in each panel mark the column density threshold (5σ level), and the solid vertical lines mark the mean column densities. We list in each panel the mean column density ⟨N⟩, the power-law index s (the optimized fit, solid line), and s^* (the fit to all data, dashed line). For the ¹³CO N-PDF, we also list the log-normal width σ_LN. Error bars are calculated from Poisson statistics.