Abbott, B. P.B. P.AbbottAbbott, R.R.AbbottAbbott, T. D.T. D.AbbottAbernathy, M. R.M. R.AbernathyAcernese, F.F.AcerneseAckley, K.K.AckleyAdams, C.C.AdamsAdams, T.T.AdamsAddesso, P.P.AddessoAdhikari, R. X.R. X.AdhikariAdya, V. B.V. B.AdyaAffeldt, C.C.AffeldtAgathos, M.M.AgathosAgatsuma, K.K.AgatsumaAggarwal, N.N.AggarwalAguiar, O. D.O. D.AguiarAiello, L.L.AielloAin, A.A.AinAjith, P.P.AjithAllen, B.B.AllenAllocca, A.A.AlloccaAltin, P. A.P. A.AltinAnderson, S. B.S. B.AndersonAnderson, W. G.W. G.AndersonArai, K.K.AraiAraya, M. C.M. C.ArayaArceneaux, C. C.C. C.ArceneauxAreeda, J. S.J. S.AreedaArnaud, N.N.ArnaudArun, K. G.K. G.ArunAscenzi, S.S.AscenziAshton, G.G.AshtonAst, M.M.AstAston, S. M.S. M.AstonAstone, P.P.AstoneAufmuth, P.P.AufmuthAulbert, C.C.AulbertBabak, S.S.BabakBacon, P.P.BaconBader, M. K.M.M. K.M.BaderBaker, P. T.P. T.BakerBaldaccini, F.F.BaldacciniBallardin, G.G.BallardinBallmer, S. W.S. W.BallmerBarayoga, J. C.J. C.BarayogaBarclay, S. E.S. E.BarclayBarish, B. C.B. C.BarishBarker, D.D.BarkerBarone, F.F.BaroneBarr, B.B.BarrBarsotti, L.L.BarsottiBarsuglia, M.M.BarsugliaBarta, D.D.BartaBartlett, J.J.BartlettBartos, I.I.BartosBassiri, R.R.BassiriBasti, A.A.BastiBatch, J. C.J. C.BatchBaune, C.C.BauneBavigadda, V.V.BavigaddaBazzan, M.M.BazzanBejger, M.M.BejgerBell, A. S.A. S.BellBerger, B. K.B. K.BergerBergmann, G.G.BergmannBerry, C. P.L.C. P.L.BerryBersanetti, D.D.BersanettiBertolini, A.A.BertoliniBetzwieser, J.J.BetzwieserBhagwat, S.S.BhagwatBhandare, R.R.BhandareBilenko, I. A.I. A.BilenkoBillingsley, G.G.BillingsleyBirch, J.J.BirchBirney, R.R.BirneyBirnholtz, O.O.BirnholtzBiscans, S.S.BiscansBisht, A.A.BishtBitossi, M.M.BitossiBiwer, C.C.BiwerBizouard, M. A.M. A.BizouardBlackburn, J. K.J. K.BlackburnBlair, C. D.C. D.BlairBlair, D. G.D. G.BlairBlair, R. M.R. M.BlairBloemen, S.S.BloemenBock, O.O.BockBoer, M.M.BoerBogaert, G.G.BogaertBogan, C.C.BoganBohe, A.A.BoheBond, C.C.BondBondu, F.F.BonduBonnand, R.R.BonnandBoom, B. A.B. A.BoomBork, R.R.BorkBoschi, V.V.BoschiBose, S.S.BoseBouffanais, Y.Y.BouffanaisBozzi, A.A.Bozzi2025-08-302025-08-302016-01-0110.1103/PhysRevX.6.0410142-s2.0-84995417589https://d8.irins.org/handle/IITG2025/22012This paper presents updated estimates of source parameters for GW150914, a binary black-hole coalescence event detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 [Abbott et al. Phys. Rev. Lett. 116, 061102 (2016).]. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] presented parameter estimation of the source using a 13-dimensional, phenomenological precessing-spin model (precessing IMRPhenom) and an 11-dimensional nonprecessing effective-one body (EOB) model calibrated to numerical-relativity simulations, which forces spin alignment (nonprecessing EOBNR). Here, we present new results that include a 15-dimensional precessingspin waveform model (precessing EOBNR) developed within the EOB formalism. We find good agreement with the parameters estimated previously [Abbott et al. Phys. Rev. Lett. 116, 241102 (2016).], and we quote updated component masses of 35 ⁺⁵ <inf>-3</inf> M· and 30 ⁺⁵ <inf>-3</inf> M· (where errors correspond to 90% symmetric credible intervals). We also present slightly tighter constraints on the dimensionless spin magnitudes of the two black holes, with a primary spin estimate < 0.65 and a secondary spin estimate < 0.75 at 90% probability. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] estimated the systematic parameter-extraction errors due to waveform-model uncertainty by combining the posterior probability densities of precessing IMRPhenom and nonprecessing EOBNR. Here, we find that the two precessing-spin models are in closer agreement, suggesting that these systematic errors are smaller than previously quoted.falseArticlehttp://link.aps.org/pdf/10.1103/PhysRevX.6.041014216033082016139041014arJournal110