filament radius of 1 $h^{-1}$Mpc does result in a slightly lower mean signal (i.e. $\sim$10-50$\%$), since some filaments are less wide and thus empty regions around the filaments will be included in the integration. The scatter for this large radius does decrease, since then most of the underlying density field of the filaments will be encapsulated by the cylinders around the filament spines, even if there is a slight misalignment. Because a larger physical radius also results in a larger area on the sky, we take the radius of 0.5 $h^{-1}$Mpc to avoid having to integrate over too large angular scales.\
The distribution of the mean filament signal as a function of the filament length is shown in Fig. \[fig:filsigs\]. The plot shows that there is a large range of mean signals for these filaments due to the different environments inside them. Howver, most of the low density gas sits at brightness temperatures around the median value of a few times $\sim10^{-7}$ K in this distribution. This corresponds to an HI column density of $\sim2-5\times10^{13}\,\mathrm{cm}^{-2}$ for a 100 km $\mathrm{s}^{-1}$ velocity width. In the inner most dense parts of the filaments they tend to be brighter and some dense clumps 