Results of the Plummer fits to OMC-3 filament segment A that was measured using MIR extinction. Frame c shows the filament column densities (units 10²¹ cm⁻²) as a 2D image, the filament running vertically in the plot. The top row contains the median profile. Frame a shows the fit residuals. Frame d shows the parameter estimates along the filament. The shaded regions correspond to different percentile ranges of MCMC samples: [1, 99]% in dark grey, [10, 90]% in light grey, and [25, 75]% in red. The MCMC median values are plotted as solid white curves. The values from separate χ² minimisation are plotted with dashed black curves. The vertical dashed light green lines (frame b and frame d show the median of the parameter values in the individual least-squares fits, while the white half-circles at the top of frame d correspond to the fit to the median profile. Frame b shows histograms of the parameter distributions based on MCMC samples over all profiles.