Pulsar timing array constraints on the induced gravitational waves
Abstract
If the black holes detected by LIGO/VIRGO are primordial black holes (PBHs) sourcing from a large primordial curvature perturbation on small scales, the corresponding induced gravitational waves (GWs) would peak at nanohertz that is detectable by the current and future observations of pulsar timing array (PTA). In this paper we show that with the mass function estimated from the merger rate of LIGO O1 and O2 events, the induced GWs from such a curvature perturbation with a Gaussian narrow peak at some small scale would be in a seemingly mild tension with current constraints from PTA. However, if the curvature perturbation is of localtype nonGaussianity with a nonlinear parameter f_{NL}gtrsimScript O(10), the tension could be relieved. Nevertheless, such an induced GWs must be detectable by the Square Kilometer Array in a decade or less.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 October 2019
 DOI:
 10.1088/14757516/2019/10/059
 arXiv:
 arXiv:1907.06372
 Bibcode:
 2019JCAP...10..059C
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Theory
 EPrint:
 23 pages, 7 figures