Top: M_ap(θ₀) (Eq. (34)) as a function of the “aperture” θ₀. The filter function u(x) defined by Eq. (38), using x₀ = 0.5, has been used such that for M_ap(θ₀), the annulus [θ₀/ (2θ_E),θ₀/θ_E] is probed. The black curve shows M_ap for the NIS profile and the blue curves for the SPT-transformed profiles with γ_p = 0.05 and various values of f₂. The green curve shows M_ap(θ₀) for an MST transformed version of the NIS profile. Bottom: ratio between M_ap derived for the various transformed profiles and for the original NIS profile.