Similar to Fig. 2 but after adding realistic noise to a Plummer-like model filament with p = 1.7. (a) Intrinsic radial profile (solid black curve) compared to the profile that would be observed after convolution with the beam (purple curve with red error bars) in the presence of typical background noise with a Kolmogorov-like power spectrum (see Appendix C). The dash-dotted green curve is the Gaussian beam, here assumed to be . (b) Measured HP diameter against HPBW spatial resolution, prior to deconvolution (hd or D_HP, blue curve with error bars) and after deconvolution (, red curve with error bars), for the model including noise, whose one realization is shown in panel a (see Appendix C for details). For comparison, the horizontal black line marks the intrinsic diameter, , of the model, and the green line is the beam HPBW. The vertical dotted segments at the bottom mark the spatial resolutions of the Arzoumanian et al. (2019) measurements assuming pc for all HGBS filaments.