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arXiv · 2306.17149

The recent gravitational wave observation by pulsar timing arrays and primordial black holes: the importance of non-gaussianities

Gabriele Franciolini·Antonio Junior Iovino·Ville Vaskonen·Hardi Veermae
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Abstract

We study whether the signal seen by pulsar timing arrays (PTAs) may originate from gravitational waves (GWs) induced by large primordial perturbations. Such perturbations may be accompanied by a sizeable primordial black hole (PBH) abundance. We improve existing analyses and show that PBH overproduction disfavors Gaussian scenarios for scalar-induced GWs at 2{\sigma} and single-field inflationary scenarios, accounting for non-Gaussianity, at 3{\sigma} as the explanation of the most constraining NANOGrav 15-year data. This tension can be relaxed in models where non-Gaussianites suppress the PBH abundance. On the flip side, the PTA data does not constrain the abundance of PBHs.

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Gabriele Franciolini, Antonio Junior Iovino, Ville Vaskonen, Hardi Veermae. 2023-06-29. The recent gravitational wave observation by pulsar timing arrays and primordial black holes: the importance of non-gaussianities. https://doi.org/10.1103/physrevlett.131.201401

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