TY - JOUR
T1 - GW230814
T2 - Investigation of a Loud Gravitational-wave Signal Observed with a Single Detector
AU - Abac, A. G.
AU - Abouelfettouh, I.
AU - Acernese, F.
AU - Ackley, K.
AU - Adamcewicz, C.
AU - Adhicary, S.
AU - Adhikari, D.
AU - Adhikari, N.
AU - Adhikari, R. X.
AU - Adkins, V. K.
AU - Afroz, S.
AU - Agapito, A.
AU - Agarwal, D.
AU - Agathos, M.
AU - Aggarwal, N.
AU - Aggarwal, S.
AU - Aguiar, O. D.
AU - Ahrend, I. L.
AU - Aiello, L.
AU - Ain, A.
AU - Ajith, P.
AU - Akutsu, T.
AU - Albanesi, S.
AU - Ali, W.
AU - Al-Kershi, S.
AU - Alléné, C.
AU - Allocca, A.
AU - Al-Shammari, S.
AU - Altin, P. A.
AU - Alvarez-Lopez, S.
AU - Amar, W.
AU - Amarasinghe, O.
AU - Amato, A.
AU - Amicucci, F.
AU - Amra, C.
AU - Ananyeva, A.
AU - Anderson, S. B.
AU - Anderson, W. G.
AU - Andia, M.
AU - Ando, M.
AU - Andrés-Carcasona, M.
AU - Andric, T.
AU - Anglin, J.
AU - Ansoldi, S.
AU - Antelis, J. M.
AU - Antier, S.
AU - Aoumi, M.
AU - Appavuravther, E. Z.
AU - Appert, S.
AU - Apple, S. K.
AU - LIGO Scientific Collaboration
AU - Virgo Collaboration
AU - KAGRA Collaboration
AU - Bertolini, Alessandro
AU - Danilishin, Stefan
AU - Diksha, Diksha
AU - Guo, Yuefan
AU - Hild, Stefan
AU - Iandolo, Guido Alex
AU - Koekoek, Gideon
AU - Kranzhoff, Luise
AU - Massaro, Luca
AU - Silenzi, Laura
AU - Steinlechner, Jessica
AU - Steinlechner, Sebastian
AU - van den Brand, Johannes
AU - Vardaro, Marco
AU - Wöhler, Janis
N1 - Funding Information:
This material is based on work supported by NSF\u2019s LIGO Laboratory, which is a major facility fully funded by the National Science Foundation. The authors also gratefully acknowledge the support of the Science and Technology Facilities Council (STFC) of the United Kingdom, the Max-Planck-Society (MPS), and the State of Niedersachsen/Germany for support of the construction of Advanced LIGO and construction and operation of the GEO 600 detector. Additional support for Advanced LIGO was provided by the Australian Research Council. The authors gratefully acknowledge the Italian Istituto Nazionale di Fisica Nucleare (INFN), the French Centre National de la Recherche Scientifique (CNRS), and the Netherlands Organization for Scientific Research (NWO) for the construction and operation of the Virgo detector and the creation and support of the EGO consortium. The authors also gratefully acknowledge research support from these agencies, as well as by the Council of Scientific and Industrial Research of India; the Department of Science and Technology, India; the Science & Engineering Research Board (SERB), India; the Ministry of Human Resource Development, India; the Spanish Agencia Estatal de Investigaci\u00F3n (AEI); the Spanish Ministerio de Ciencia, Innovaci\u00F3n y Universidades the European Union NextGenerationEU/PRTR (PRTR-C17.I1); the ICSC\u2014CentroNazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing, funded by the European Union NextGenerationEU; the Comunitat Auton\u00F2ma de les Illes Balears through the Conselleria d\u2019Educaci\u00F3 i Universitats; the Conselleria d\u2019Innovaci\u00F3, Universitats, Ci\u00E8ncia i Societat Digital de la Generalitat Valenciana and the CERCA Programme Generalitat de Catalunya, Spain; the Polish National Agency for Academic Exchange; the National Science Centre of Poland and the European Union\u2014European Regional Development Fund; the Foundation for Polish Science (FNP); the Polish Ministry of Science and Higher Education; the Swiss National Science Foundation (SNSF); the Russian Science Foundation; the European Commission; the European Social Funds (ESF); the European Regional Development Funds (ERDF); the Royal Society; the Scottish Funding Council; the Scottish Universities Physics Alliance; the Hungarian Scientific Research Fund (OTKA); the French Lyon Institute of Origins (LIO); the Belgian Fonds de la Recherche Scientifique (FRS-FNRS); Actions de Recherche Concert\u00E9es (ARC) and Fonds Wetenschappelijk Onderzoek\u2014Vlaanderen (FWO), Belgium; the Paris I^le-de-France Region; the National Research, Development and Innovation Office of Hungary (NKFIH); the National Research Foundation of Korea; the Natural Sciences and Engineering Research Council of Canada (NSERC); the Canadian Foundation for Innovation (CFI); the Brazilian Ministry of Science, Technology, and Innovations; the International Center for Theoretical Physics South American Institute for Fundamental Research (ICTP-SAIFR); the Research Grants Council of Hong Kong; the National Natural Science Foundation of China (NSFC); the Israel Science Foundation (ISF); the US\u2212Israel Binational Science Fund (BSF); the Leverhulme Trust; the Research Corporation; the National Science and Technology Council (NSTC), Taiwan; the United States Department of Energy; and the Kavli Foundation. The authors gratefully acknowledge the support of the NSF, STFC, INFN, and CNRS for provision of computational resources.This work was supported by MEXT, the JSPS Leading-edge Research Infrastructure Program, JSPS Grant-in-Aid for Specially Promoted Research 26000005, JSPS Grant-in-Aid for Scientific Research on Innovative Areas 2402: 24103006, 24103005, and 2905: JP17H06358, JP17H06361, and JP17H06364, JSPS Core-to-Core Program A. Advanced Research Networks, JSPS Grants-in-Aid for Scientific Research (S) 17H06133 and 20H05639, JSPS Grant-in-Aid for Transformative Research Areas (A) 20A203: JP20H05854, the joint research program of the Institute for Cosmic Ray Research, University of Tokyo, the National Research Foundation (NRF), the Computing Infrastructure Project of the Global Science experimental Data hub Center (GSDC) at KISTI, the Korea Astronomy and Space Science Institute (KASI), the Ministry of Science and ICT (MSIT) in Korea, Academia Sinica (AS), the AS Grid Center (ASGC) and the National Science and Technology Council (NSTC) in Taiwan under grants including the Science Vanguard Research Program, the Advanced Technology Center (ATC) of NAOJ, and the Mechanical Engineering Center of KEK.Additional acknowledgments for support of individual authors may be found in the following document:https://dcc.ligo.org/LIGO-M2300033/public. For the purpose of open access, the authors have applied a Creative Commons Attribution (CC BY) license to any Author Accepted Manuscript version arising. We request that citations to this article use \u201CA. G. Abacet al.(LIGO\u2013Virgo\u2013KAGRA Collaboration), ...\u201D or similar phrasing, depending on journal convention.The NR simulations were run at thesonicHigh Performance Computing facility at ICTS-TIFR, Bengaluru, India, supported by the Department of Atomic Energy, Government of India, under project No. RTI4001.Software: The following software was used in this research: Asimov (D. Williamset al.2023); Astropy (Astropy Collaborationet al.2013,2018,2022); BayesWave (N. J. Cornish & T. B Littenberg2024); Bilby (G. Ashtonet al.2019; I. M. Romero-Shawet al.2020; R. J. E. Smithet al.2020); Bilby-TGR (G. Ashtonet al.2025); CPNest (J. Veitchet al.2025); Dynesty (S. Koposovet al.2024); FTI (A. K. Mehtaet al.2023); GOLUM (J. Janquartet al.2021a); GraceDB (GraceDB developers2023); Gravelamps (M. Wright & M. Hendry2022; A. Liuet al.2023); GSTLAL (C. Messicket al.2017; S. Sachdevet al.2019; K. Cannonet al.2021; C. Hannaet al.2020; L. Tsukadaet al.2023; B. Ewinget al.2024; S. Sakonet al.2024); GWpy (D. M. Macleodet al.2021); LALSuite (LIGO Scientific Collaborationet al.2018; K. Wette2020); MBTA (F. Aubinet al.2021); PESummary (C. Hoy & V. Raymond2021); PyCBC (A. Nitzet al.2024); PyRing (G. Carulloet al.2019,2025); PySEOBNR (D. P. Mihaylovet al.2025); QNMRF (S. Maet al.2022,2023a,2023b); Ringdown (M. Isi & W. M. Farr2021); Spec (L. Kidderet al.2025); TIGER (M. Agathoset al.2014; J. Meidamet al.2018; S. Royet al.2026).Late in the preparation of this manuscript, an error was discovered in the likelihood evaluation within Bilby (see C. Talbotet al.2025; A. G. Abacet al.2026e, for details). Consequently, we repeated all GR PE runs and the pSEOBNR analysis using the corrected likelihood. A complete rerun of the simulated signals (including pSEOBNR) and the FTI, TIGER, PCA, and MDR tests was not feasible. However, since the reruns validated that a likelihood reweighting would produce consistent results, a complete rerun was deemed unnecessary. Therefore, we have updated the results from these specific analyses via reweighting, which appropriately corrects the posterior distributions, log-likelihoods, and Bayes factors.
Publisher Copyright:
© 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
PY - 2026/6/20
Y1 - 2026/6/20
N2 - 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 (Formula presented) m1=33.7-2.2+2.9M? and (Formula presented) m2=28.2-3.1+2.2M? and a small effective inspiral spin (Formula presented) ?eff=-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.
AB - 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 (Formula presented) m1=33.7-2.2+2.9M? and (Formula presented) m2=28.2-3.1+2.2M? and a small effective inspiral spin (Formula presented) ?eff=-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.
KW - Black hole physics (159)
KW - Compact binary stars (283)
KW - Gravitational wave astronomy (675)
KW - Gravitational wave sources (677)
KW - Gravitational waves (678)
KW - LIGO (920)
KW - Quasinormal modes (1320)
U2 - 10.3847/2041-8213/ae2ad3
DO - 10.3847/2041-8213/ae2ad3
M3 - Article
SN - 2041-8205
VL - 1004
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L23
ER -