Primordial Black Holes for the LIGO Events in the Axion-like Curvaton Model

TL;DR

This paper explores whether primordial black holes generated in the axion-like curvaton model can explain LIGO's gravitational wave signals, considering the effects of non-Gaussianity and constraints from pulsar timing arrays.

Contribution

It revises PBH formation in the axion-like curvaton model and assesses its viability as the source of LIGO-detected gravitational waves, including non-Gaussian effects and observational constraints.

Findings

PBHs can account for LIGO events within model constraints

Non-Gaussianity allows smaller primordial perturbations for PBH production

Model remains consistent with pulsar timing array constraints

Abstract

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.