GW230814: Investigation of a loud gravitational-wave signal observed with a single detector

Abac, A. G., Abouelfettouh, I., Acernese, F., Ackley, K., Adamcewicz, C., Al-Shammari, S., Amarasinghege, O., Bergamin, F., Divyajyoti, D. ORCID: https://orcid.org/0000-0002-2787-1012, Dooley, K. L. ORCID: https://orcid.org/0000-0002-1636-0233, Fairhurst, S. ORCID: https://orcid.org/0000-0001-8480-1961, Gottel, A. S. ORCID: https://orcid.org/0000-0002-6215-4641, Grote, H. ORCID: https://orcid.org/0000-0002-0797-3943, Hannam, M. D. ORCID: https://orcid.org/0000-0001-5571-325X, Higginbotham, S., Javed, W. ORCID: https://orcid.org/0009-0009-1471-7890, Kinnear, M., Kokeyama, K. ORCID: https://orcid.org/0000-0002-2896-1992, Kuntimaddi, N., MacLeod, D. M. ORCID: https://orcid.org/0000-0002-1395-8694, Mahapatra, P., Norman, M., North, C., Patra, A., Patterson, B. G., Pearce, T., Raymond, V. ORCID: https://orcid.org/0000-0003-0066-0095, Sathyaprakash, B. S. ORCID: https://orcid.org/0000-0003-3845-7586, Schutz, B. F. ORCID: https://orcid.org/0000-0001-9487-6983, Singh, M., Skliris, V., Sutton, P. J. ORCID: https://orcid.org/0000-0003-1614-3922, Tanioka, S. and Tsang, T. 2026. GW230814: Investigation of a loud gravitational-wave signal observed with a single detector. The Astrophysical Journal Letters 1004 (2) , L23. 10.3847/2041-8213/ae2ad3

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Abstract

GW230814, detected by the LIGO Livingston observatory with a signal-to-noise ratio of 42.4, represents the loudest gravitational-wave signal in the GWTC-4.0 catalog. Its source is consistent with a binary black hole coalescence with component masses m1=33.7−2.2+2.9M⊙ and m2=28.2−3.1+2.2M⊙ and a small effective inspiral spin χeff=−0.01−0.07+0.06 . The high signal-to-noise ratio enabled us to detect an ℓ = ∣m∣ = 4 mode in the inspiral–merger–ringdown signal for the first time (with Bayes factor ≈10), as well as enabling a range of tests of consistency between theoretical predictions and the observed waveform. While most of these tests show agreement with theoretical predictions, there are suggestions of minor deviations in the ringdown phase. Simulations that incorporate general relativity and realistic detector noise reproduce similar deviations, suggesting that they do not constitute evidence for a breakdown of general relativity. The observation of GW230814 demonstrates that the unprecedented sensitivity of the detectors enables highly significant detections with a single observatory. However, without corroborating data from a multidetector network, the ability to draw rigorous conclusions about fundamental physics remains severely limited.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Schools > Physics and Astronomy
Additional Information:	For full author list see https://doi.org/10.3847/2041-8213/ae2ad3 License information from Publisher: LICENSE 1: URL: https://creativecommons.org/licenses/by/4.0/, Type: cc-by
Publisher:	American Astronomical Society
ISSN:	2041-8205
Date of First Compliant Deposit:	24 June 2026
Date of Acceptance:	25 November 2025
Last Modified:	07 Aug 2026 22:37
URI:	https://orca.cardiff.ac.uk/id/eprint/187733

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