Probing past mergers of supermassive black holes with pulsar timing arrays: The role of pulsar terms

[2604.20975] Probing past mergers of supermassive black holes with pulsar timing arrays: The role of pulsar terms Skip to main content Search Submit Donate Log in Astrophysics > High Energy Astrophysical Phenomena arXiv:2604.20975 (astro-ph) [Submitted on 22 Apr 2026 ( v1 ), last revised 24 Aug 2026 (this version, v2)] Title: Probing past mergers of supermassive black holes with pulsar timing arrays: The role of pulsar terms Authors: Hippolyte Quelquejay Leclere View PDF HTML (experimental) Abstract: By monitoring the times of arrival of radio pulses from millisecond pulsars, Pulsar Timing Arrays (PTAs) serve as unique gravitational wave (GW) laboratories in the nanohertz band. To date, the primary astrophysical sources of GWs targeted in this frequency range have been inspiraling supermassive black hole binaries (SMBHBs) on circular and eccentric orbits. In this work, we demonstrate that, thanks to the so-called pulsar term in the timing residual waveform of GW signals, PTAs can probe individual SMBHBs that merged before timing observations began. We refer to the latter as zombie binaries. Using SMBHB population models consistent with current PTA constraints, we find that while the probability of detecting such systems in existing PTA datasets remains low, the Square Kilometer Array observatory is expected to achieve sufficient sensitivity to have a few zombie binaries with optimal matched filter signal-to-noise ratios exceeding 3 in its data. Although their confident identification might be challenging, this new class of PTA sources opens a novel window for studying the most massive SMBHBs in our local universe. Comments: 12 pages, 5 figures. Published in PRD. Revised version incorporating the referee' comments Subjects: High Energy Astrophysical Phenomena (astro-ph.HE) ; General Relativity and Quantum Cosmology (gr-qc) Cite as: arXiv:2604.20975 [astro-ph.HE] (or arXiv:2604.20975v2 [astro-ph.HE] for this version) https://doi.org/10.48550/arXiv.2604.20975 Focus to learn more arXiv-issued DOI via DataCite Related DOI : https://doi.org/10.1103/9wq2-gqkh Focus to learn more DOI(s) linking to related resources Submission history From: Hippolyte Quelquejay Leclere [ view email ] [v1] Wed, 22 Apr 2026 18:06:01 UTC (1,675 KB) [v2] Mon, 24 Aug 2026 20:26:40 UTC (1,555 KB) Full-text links: Access Paper: View PDF HTML (experimental) TeX Source view license Additional Features Audio Summary Current browse context: astro-ph.HE < prev | next > new | recent | 2026-04 Change to browse by: astro-ph gr-qc References & Citations INSPIRE HEP SciX Google Scholar Semantic Scholar export BibTeX citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer ( What is the Explorer? ) Connected Papers Toggle Connected Papers ( What is Connected Papers? ) Litmaps Toggle Litmaps ( What is Litmaps? ) scite.ai Toggle scite Smart Citations ( What are Smart Citations? ) Code, Data, Media Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv ( What is alphaXiv? ) Links to Code Toggle CatalyzeX Code Finder for Papers ( What is CatalyzeX? ) DagsHub Toggle DagsHub ( What is DagsHub? ) GotitPub Toggle Gotit.pub ( What is GotitPub? ) Huggingface Toggle Hugging Face ( What is Huggingface? ) ScienceCast Toggle ScienceCast ( What is ScienceCast? ) Demos Demos Replicate Toggle Replicate ( What is Replicate? ) Spaces Toggle Hugging Face Spaces ( What is Spaces? ) Spaces Toggle TXYZ.AI ( What is TXYZ.AI? ) Related Papers Recommenders and Search Tools Link to Influence Flower Influence Flower ( What are Influence Flowers? ) Core recommender toggle CORE Recommender ( What is CORE? ) IArxiv recommender toggle IArxiv Recommender ( What is IArxiv? ) Author Venue Institution Topic About arXivLabs arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them. Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs . Which authors of this paper are endorsers? | Disable MathJax ( What is MathJax? ) We gratefully acknowledge support from our major funders , member institutions , and all contributors. About · Help · Contact · Subscribe · Copyright · Privacy · Accessibility · Operational Status (opens in new tab) Major funding support from (opens in new tab) (opens in new tab) (opens in new tab)

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