Top panels: expected two-point correlation function ⟨κκ′ | pk⟩ in units of for a 2D power spectrum with spectral index n_s = 0 and a central peak of height and eigenvalues and in r_z. Different values of θ, the angle between the major axis of the ellipse (i.e. smaller curvature) and the first point on the annulus between 0 and π/ 2 are shown from left to right. ψ is the angle between r_x and r_y and r is the separation to the central peak (in units of the smoothing length) so that the shown value corresponds to the correlation function between this point, r_y and that on the positive x-axis at the same radius, r_x. The values we chose here correspond to the most likely height and curvatures of a peak (and do not depend on the spectral index). Bottom panels: same as top panels for ν_r = 3. The corresponding most likely curvatures of the peak are λ_1r = − 0.94 and λ_2r = − 1.6.