More on the Non-Gaussianity of Perturbations in a Non-Minimal
  Inflationary Model
  We study nonlinear cosmological perturbations and their possible non-Gaussian
character in an extended non-minimal inflation where gravity is coupled
non-minimally to both the scalar field and its derivatives. By expansion of the
action up to the third order, we focus on the non-linearity and non-Gaussianity
of perturbations in comparison with recent observational data. By adopting an
inflation potential of the form V(phi) = (1/n)(lambda)(phi)^n, we show that for
n = 4, for instance, this extended model is consistent with observation if
0.013 <lambda< 0.095 in appropriate units. By restricting the equilateral
amplitude of non-Gaussianity to the observationally viable values, the coupling
parameter lambda is constraint to the values lambda< 0.1.
