def nfwAlpha(self, R, Rs, rho0, r_trunc, ax_x, ax_y):
        """
        deflection angel of NFW profile along the projection to coordinate axis

        :param R: radius of interest
        :type R: float/numpy array
        :param Rs: scale radius
        :type Rs: float
        :param rho0: density normalization (characteristic density)
        :type rho0: float
        :param r200: radius of (sub)halo
        :type r200: float>0
        :param axis: projection to either x- or y-axis
        :type axis: same as R
        :return: Epsilon(R) projected density at radius R
        """
        if isinstance(R, int) or isinstance(R, float):
            R = max(R, 0.00001)
        else:
            R[R <= 0.00001] = 0.00001

        x = R / Rs
        tau = float(r_trunc) / Rs
        gx = self._g(x, tau)
        a = 4 * rho0 * Rs * gx / x ** 2
        return a * ax_x, a * ax_y