Abbott, R.R.AbbottAbbott, T. D.T. D.AbbottAbraham, S.S.AbrahamAcernese, F.F.AcerneseAckley, K.K.AckleyAdams, A.A.AdamsAdams, C.C.AdamsAdhikari, R. X.R. X.AdhikariAdya, V. B.V. B.AdyaAffeldt, C.C.AffeldtAgarwal, D.D.AgarwalAgathos, M.M.AgathosAgatsuma, K.K.AgatsumaAggarwal, N.N.AggarwalAguiar, O. D.O. D.AguiarAiello, L.L.AielloAin, A.A.AinAjith, P.P.AjithAkutsu, T.T.AkutsuAleman, K. M.K. M.AlemanAllen, G.G.AllenAllocca, A.A.AlloccaAltin, P. A.P. A.AltinAmato, A.A.AmatoAnand, S.S.AnandAnanyeva, A.A.AnanyevaAnderson, S. B.S. B.AndersonAnderson, W. G.W. G.AndersonAndo, M.M.AndoAngelova, S. V.S. V.AngelovaAnsoldi, S.S.AnsoldiAntelis, J. M.J. M.AntelisAntier, S.S.AntierAppert, S.S.AppertArai, KoyaKoyaAraiArai, KojiKojiAraiArai, Y.Y.AraiAraki, S.S.ArakiAraya, A.A.ArayaAraya, M. C.M. C.ArayaAreeda, J. S.J. S.AreedaArene, M.M.AreneAritomi, N.N.AritomiArnaud, N.N.ArnaudAronson, S. M.S. M.AronsonArun, K. G.K. G.ArunAsada, H.H.AsadaAsali, Y.Y.AsaliAshton, G.G.AshtonAso, Y.Y.AsoAston, S. M.S. M.AstonAstone, P.P.AstoneAubin, F.F.AubinAufmuth, P.P.AufmuthAultoneal, K.K.AultonealAustin, C.C.AustinBabak, S.S.BabakBadaracco, F.F.BadaraccoBader, M. K.M.M. K.M.BaderBae, S.S.BaeBae, Y.Y.BaeBaer, A. M.A. M.BaerBagnasco, S.S.BagnascoBai, Y.Y.BaiBaiotti, L.L.BaiottiBaird, J.J.BairdBajpai, R.R.BajpaiBall, M.M.BallBallardin, G.G.BallardinBallmer, S. W.S. W.BallmerBals, M.M.BalsBalsamo, A.A.BalsamoBaltus, G.G.BaltusBanagiri, S.S.BanagiriBankar, D.D.BankarBankar, R. S.R. S.BankarBarayoga, J. C.J. C.BarayogaBarbieri, C.C.BarbieriBarish, B. C.B. C.BarishBarker, D.D.BarkerBarneo, P.P.BarneoBarnum, S.S.BarnumBarone, F.F.BaroneBarr, B.B.BarrBarsotti, L.L.BarsottiBarsuglia, M.M.BarsugliaBarta, D.D.BartaBartlett, J.J.BartlettBarton, M. A.M. A.BartonBartos, I.I.BartosBassiri, R.R.BassiriBasti, A.A.BastiBawaj, M.M.BawajBayley, J. C.J. C.BayleyBaylor, A. C.A. C.BaylorBazzan, M.M.BazzanB�csy, B.B.B�csyBedakihale, V. M.V. M.BedakihaleBejger, M.M.BejgerBelahcene, I.I.Belahcene2025-08-312025-08-312021-06-0110.3847/2041-8213/abffcd2-s2.0-85108553505http://repository.iitgn.ac.in/handle/IITG2025/25434We present a search for quasi-monochromatic gravitational-wave signals from the young, energetic X-ray pulsar PSR J0537-6910 using data from the second and third observing runs of LIGO and Virgo. The search is enabled by a contemporaneous timing ephemeris obtained using Neutron star Interior Composition Explorer (NICER) data. The NICER ephemeris has also been extended through 2020 October and includes three new glitches. PSR J0537-6910 has the largest spin-down luminosity of any pulsar and exhibits fRequent and strong glitches. Analyses of its long-term and interglitch braking indices provide intriguing evidence that its spin-down energy budget may include gravitational-wave emission from a time-varying mass quadrupole moment. Its 62 Hz rotation frequency also puts its possible gravitational-wave emission in the most sensitive band of the LIGO/Virgo detectors. Motivated by these considerations, we search for gravitational-wave emission at both once and twice the rotation frequency from PSR J0537-6910. We find no signal, however, and report upper limits. Assuming a rigidly rotating triaxial star, our constraints reach below the gravitational-wave spin-down limit for this star for the first time by more than a factor of 2 and limit gravitational waves from the l = m = 2 mode to account for less than 14% of the spin-down energy budget. The fiducial equatorial ellipticity is constrained to less than about 3 ×10-5, which is the third best constraint for any young pulsar.falseGravitational wavesArticlehttps://kclpure.kcl.ac.uk/portal/en/publications/68b184b0-65f4-479b-b926-2ba73f2ad83c204182131 June 202139L27arJournal39