Primordial Black Holes for the LIGO Events in the Axion-like Curvaton
  Model
  We revise primordial black hole (PBH) formation in the axion-like curvaton
model and investigate whether PBHs formed in this model can be the origin of
the gravtitational wave (GW) signals detected by the Advanced LIGO. In this
model, small-scale curvature perturbations with large amplitude are generated,
which is essential for PBH formation. On the other hand, large curvature
perturbations also become a source of primordial GWs by their second-order
effects. Severe constraints are imposed on such GWs by pulsar timing array
(PTA) experiments. We also check the consistency of the model with these
constraints. In this analysis, it is important to take into account the effect
of non-Gaussianity, which is generated easily in the curvaton model. We see
that, if there are non-Gaussianities, the fixed amount of PBHs can be produced
with a smaller amplitude of the primordial power spectrum.
