Viable Curvaton Models from the $f_{NL}$ Parameter
  We show how to build a curvaton inflationary model motivated by
scale-dependent non-Gaussianities of cosmological perturbations. In particular,
we study the change of sign in the $f_{NL}$ parameter as a function of the
curvaton field value at horizon crossing and identify it with the cosmic
microwave background pivot scale. We devise a procedure to recover the curvaton
model that provides the desired $f_{NL}$ parameter. We then present a concrete
example of $f_{NL}$ and construct its parent model. We study the constraints
applied to this model based on considerations taken on $f_{NL}$. We show that
the hemispherical asymmetry can also be used to constrain the scale-dependence
of $f_{NL}$ and the model parameters.
