NFW Potential

NFW potential of gNFW need the following parameters: x_centre, y_centre, ellipticite, angle_pos, alpha, scale_radius_kpc, concentration, z_lens .

The Newtonian (spherical) gNFW potential is:

\Phi (x) = \rho_S x^{-\alpha} (1 + x)^{- (3 - \alpha)}

where x = r / r_S is a redimensionned radius (see Limousin et al. 2008 eq. 1).

\alpha = 1.0 corresponds to a regular NFW profile.

Example of lenstool NFW parametrisation:

potential  1
        profile              12
        x_centre             0.
        y_centre             0.
        ellipticity          0.
        angle_pos            0.
        alpha                1.
        scale_radius_kpc     30.
        concentration        5.5
        z_lens               0.2
        end

NOTE: If you want to use the generalized NFW profile, you need to prepare the lenstool.tab lookup table with this command:

make table