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| Main Authors: | , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2512.08666 |
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| _version_ | 1866911628668174336 |
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| author | Yu, Wang-Wei Allen, Bruce |
| author_facet | Yu, Wang-Wei Allen, Bruce |
| contents | Using public pulse time-of-arrival data from five pulsar timing arrays (PTAs), we search for a stationary, isotropic, and unpolarized nHz stochastic gravitational-wave background (SGWB). This analysis is more sensitive than previous individual PTA searches because the combined 121-pulsar dataset is about four times larger than any single PTA's. For pulsars observed by multiple PTAs, we employ a new "direct combination" method to merge their astrophysical models and data. This avoids the challenge of reconciling different PTA timing models to obtain a single "best" model. A central result of our analysis is the posterior distribution of the amplitude $A_{gw}$ and exponent $γ_{gw}$ of the putative SGWB energy-density spectrum, modeled as a power law in frequency. While these results are consistent with a nonzero SGWB amplitude $A_{gw}$, the statistical significance-assessed via a Bayesian odds ratio and noise-marginalized false-alarm probabilities ($p$-values) for three detection statistics-remains below the conventional $5σ$ threshold for a confident detection. The inter-pulsar timing-residual correlation, reconstructed as a function of angle $θ$ between the pulsar lines of sight, matches the Hellings and Downs (HD) prediction. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_08666 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Stochastic gravitational-wave background search using data from five pulsar timing arrays Yu, Wang-Wei Allen, Bruce Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology Using public pulse time-of-arrival data from five pulsar timing arrays (PTAs), we search for a stationary, isotropic, and unpolarized nHz stochastic gravitational-wave background (SGWB). This analysis is more sensitive than previous individual PTA searches because the combined 121-pulsar dataset is about four times larger than any single PTA's. For pulsars observed by multiple PTAs, we employ a new "direct combination" method to merge their astrophysical models and data. This avoids the challenge of reconciling different PTA timing models to obtain a single "best" model. A central result of our analysis is the posterior distribution of the amplitude $A_{gw}$ and exponent $γ_{gw}$ of the putative SGWB energy-density spectrum, modeled as a power law in frequency. While these results are consistent with a nonzero SGWB amplitude $A_{gw}$, the statistical significance-assessed via a Bayesian odds ratio and noise-marginalized false-alarm probabilities ($p$-values) for three detection statistics-remains below the conventional $5σ$ threshold for a confident detection. The inter-pulsar timing-residual correlation, reconstructed as a function of angle $θ$ between the pulsar lines of sight, matches the Hellings and Downs (HD) prediction. |
| title | Stochastic gravitational-wave background search using data from five pulsar timing arrays |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2512.08666 |