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Table 3

Far wing kernels.

Kernel name Definition Full width half maximum

Gauss kG(r;σ) ∝ exp(−r2/ (2σ2))
Lorentz kL(r;γ) ∝ (1 + r2/γ2)-1 FWHML = γ·2
Moffat kM(r;α,β) ∝ (1 + r2/α2)β
Voigt kV(r;σ,γ) ∝ kG(r;σ) ∗ kL(r;γ)

Notes. All kernels are functions of the radial coordinate r = (x2 + y2)1/2. They are normalized in the Fourier domain by division with the value in the origin. kM is from Moffat (1969). The expression for FWHMV is accurate to within a few ? (Olivero & Longbothum 1977).

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