Central Faraday depth as a function of Faraday dispersion, measured in the observer’s frame. Dashed lines indicate σ_ϕ = 1.22(ϕ_c − 16 rad m⁻²), where 16 rad m⁻² is the Faraday depth due to the Galactic foreground. One component models are indicated with brown filled circles and two component models with black and cyan stars, where black indicates the component with the lower Faraday dispersion and cyan the higher one. Components shown in Fig. 10 with a very large uncertainties are neglected here because they do not provide any constraint. The plot shows that the scatter of the central Faraday depth increases with increasing Faraday dispersion.