Searching for a waveform-agnostic gravitational wave signal in pulsar timing arrays

Fuente: arXiv
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Main Authors: Deng, Heling, Becsy, Bence, Levin, Yuri, Cornish, Neil J., Siemens, Xavier
Format: Preprint
Published: 2026
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author Deng, Heling
Becsy, Bence
Levin, Yuri
Cornish, Neil J.
Siemens, Xavier
author_facet Deng, Heling
Becsy, Bence
Levin, Yuri
Cornish, Neil J.
Siemens, Xavier
contents Pulsar timing arrays have recently provided compelling evidence for a nanohertz stochastic gravitational wave background, motivating searches for gravitational waves from localized sources. Most existing searches assume specific waveform templates, which can be computationally demanding and potentially insensitive to unexpected signals. We introduce a waveform-agnostic framework that models signal-induced timing residuals via a Fourier expansion. A Lorentzian hyperprior is imposed on the variances of the Fourier coefficients, providing a flexible spectral envelope that captures the signal's dominant frequency and bandwidth while remaining agnostic to its exact shape. Analytical marginalization over the Fourier coefficients then yields a Bayesian hierarchical framework that concurrently infers the source sky location, its frequency content, and the stochastic background. To mitigate contamination from unmodeled pulsar noise, we further allow for additional flat-spectrum features for each pulsar. Tests on simulated datasets show that the method is robust and provides a flexible tool for future PTA searches, with sensitivity to both expected and unexpected gravitational wave phenomena.
format Preprint
id arxiv_https___arxiv_org_abs_2606_00577
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Searching for a waveform-agnostic gravitational wave signal in pulsar timing arrays
Deng, Heling
Becsy, Bence
Levin, Yuri
Cornish, Neil J.
Siemens, Xavier
General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
Pulsar timing arrays have recently provided compelling evidence for a nanohertz stochastic gravitational wave background, motivating searches for gravitational waves from localized sources. Most existing searches assume specific waveform templates, which can be computationally demanding and potentially insensitive to unexpected signals. We introduce a waveform-agnostic framework that models signal-induced timing residuals via a Fourier expansion. A Lorentzian hyperprior is imposed on the variances of the Fourier coefficients, providing a flexible spectral envelope that captures the signal's dominant frequency and bandwidth while remaining agnostic to its exact shape. Analytical marginalization over the Fourier coefficients then yields a Bayesian hierarchical framework that concurrently infers the source sky location, its frequency content, and the stochastic background. To mitigate contamination from unmodeled pulsar noise, we further allow for additional flat-spectrum features for each pulsar. Tests on simulated datasets show that the method is robust and provides a flexible tool for future PTA searches, with sensitivity to both expected and unexpected gravitational wave phenomena.
title Searching for a waveform-agnostic gravitational wave signal in pulsar timing arrays
topic General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2606.00577