paper

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

arXiv:2306.17149 · doi:10.1103/PhysRevLett.131.201401

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 2σ and single-field inflationary scenarios, accounting for non-Gaussianity, at 3σ 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.

V3: Version published on PRL. 15 pages and 8 figures. Full article + supplementary materials. V1 appeared on Thu, 29 Jun 2023

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