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arXiv · 2307.04419

Constraints on primordial curvature power spectrum with pulsar timing arrays

Zhi-Qiang You·Zhu Yi·You Wu
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Abstract

The stochastic signal detected by NANOGrav, PPTA, EPTA, and CPTA can be explained by the scalar-induced gravitational waves. In order to determine the scalar-induced gravitational waves model that best fits the stochastic signal, we employ both single- and double-peak parameterizations for the power spectrum of the primordial curvature perturbations, where the single-peak scenarios include the $\delta$-function, box, lognormal, and broken power law model, and the double-peak scenario is described by the double lognormal form. Using Bayesian inference, we find that there is no significant evidence for or against the single-peak scenario over the double-peak model, with $\log$ (Bayes factors) among these models $\ln \mathcal{B} < 1$. Therefore, we cannot distinguish the different shapes of the power spectrum of the primordial curvature perturbation with the current sensitivity of pulsar timing arrays.

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Zhi-Qiang You, Zhu Yi, You Wu. 2023-07-10. Constraints on primordial curvature power spectrum with pulsar timing arrays. https://doi.org/10.1088/1475-7516%2F2023%2F11%2F065

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