http://arxiv.org/abs/2211.09450
Assuming the common-spectrum process in the NANOGrav 12.5-year dataset has an origin of scalar induced gravitational waves, we study the enhancement of primordial curvature perturbations and the mass function of primordial black holes, by performing the Bayesian parameter inference for the first time. We obtain lower limits on the spectral amplitude, i.e. $\mathcal{A}\gtrsim10^{-2}$ at 95\% confidence level, when assuming the power spectrum of primordial curvature perturbations to follow a log-normal distribution function with width $\sigma$. In the limit of $\sigma\rightarrow0$, we find that the primordial black holes with $10^{-3}-10^{-2}$ solar mass are allowed to compose at least a fraction of dark matter. Such a mass range would be shifted to more massive regimes for larger values of $\sigma$, e.g. to a regime of $10^{-2}-10^{-1}$ solar mass for $\sigma=1$. We expect that planned gravitational-wave experiments are capable to reach at least $\mathcal{A}\sim10^{-4}$ and search for the primordial black holes over the whole parameter space. In addition, importance of multi-band detector networks is emphasized to accomplish our theoretical expectation.
Z. Zhao and S. Wang
Fri, 18 Nov 22
36/70
Comments: 16 pages, 5 figures, 1 table