Non-Gaussian timing residual skewness in pulsar timing arrays
Abstract
Motivated by searches for weak primordial non-Gaussianity in the cosmic microwave background, we investigate perturbative departures from Gaussian stochastic gravitational wave background statistics using pulsar timing arrays. We consider a quadratic ansatz that shows three-point correlations at first order in the nonlinear coupling and covariance corrections at second order. We first examine the ansatz for gravitational wave helicity amplitudes. However, the timing residual bispectrum that this produces is not manifestly invariant under local polarization basis rotations for tensor and vector modes. Then, we formulate a polarization-frame-invariant phenomenological model for detector-projected amplitudes and evaluate its one-pulsar timing residual third moment with a simplified response. Our numerical benchmarks have shown that this gives a very small Gaussian-rms-normalized skewness.
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BibTeX
@misc{bernardo2026nongaussian,
title = {{Non-Gaussian timing residual skewness in pulsar timing arrays}},
author = {Reginald Christian Bernardo and Rituparna Mandal and Kin-Wang Ng},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.02735},
eprint = {2610.02735},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.02735},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Non-Gaussian timing residual skewness in pulsar timing arrays
AU - Reginald Christian Bernardo
AU - Rituparna Mandal
AU - Kin-Wang Ng
PY - 2026
DA - 2026/10/02
PB - arXiv
DO - 10.48550/arxiv.2610.02735
UR - https://arxiv.org/abs/2610.02735
AB - Motivated by searches for weak primordial non-Gaussianity in the cosmic microwave background, we investigate perturbative departures from Gaussian stochastic gravitational wave background statistics using pulsar timing arrays. We consider a quadratic ansatz that shows three-point correlations at first order in the nonlinear coupling and covariance corrections at second order. We first examine the ansatz for gravitational wave helicity amplitudes. However, the timing residual bispectrum that this produces is not manifestly invariant under local polarization basis rotations for tensor and vector modes. Then, we formulate a polarization-frame-invariant phenomenological model for detector-projected amplitudes and evaluate its one-pulsar timing residual third moment with a simplified response. Our numerical benchmarks have shown that this gives a very small Gaussian-rms-normalized skewness.
ER -