Illustration of how we compute the pixel-selection cutoff in Stokes I in the 1.3 mm observation of the B335 core. Top: evolution of the S/N of the polarized intensity, i.e., P∕σ_P, as a functionof the total intensity Stokes I in Jy str⁻¹. The dot-dashed horizontal black line is at the value of P∕σ_P = 5. The dotted vertical line is the selected cutoff in Stokes I described in Sect. 3.1. The dot-dashed vertical line is the 5σ_I value. The solid line is the running mean, which is calculated along the Stokes I; the shaded area represents ± the standard deviation of the Gaussian fit performed on each bin. Bottom: for the selected pixels as a function of the total intensity. To the left of the cutoff in Stokes I (the red dotted line, plotted as in the top panel), the points are no longer plotted and the running mean turns in a translucent dashed line. Each color corresponds to an angular resolution: red is the original resolution, whereas blue and green are 4 × and 9 × lower resolution (in terms of beam area), respectively. We note that, as expected, one see that decreasing the resolution, and thus increasing the spatial length of the lag, causes on the dispersion to increase as well, on average (see Sect. 2.1).