Aasi, J.J.AasiAbbott, B. P.B. P.AbbottAbbott, R.R.AbbottAbbott, T.T.AbbottAbernathy, M. R.M. R.AbernathyAcernese, F.F.AcerneseAckley, K.K.AckleyAdams, C.C.AdamsAdams, T.T.AdamsAdams, T.T.AdamsAddesso, P.P.AddessoAdhikari, R. X.R. X.AdhikariAdya, V.V.AdyaAffeldt, C.C.AffeldtAgathos, M.M.AgathosAgatsuma, K.K.AgatsumaAggarwal, N.N.AggarwalAguiar, O. D.O. D.AguiarAin, A.A.AinAjith, P.P.AjithAlemic, A.A.AlemicAllen, B.B.AllenAllocca, A.A.AlloccaAmariutei, D.D.AmariuteiAnderson, S. B.S. B.AndersonAnderson, W. G.W. G.AndersonArai, K.K.AraiAraya, M. C.M. C.ArayaArceneaux, C.C.ArceneauxAreeda, J. S.J. S.AreedaAshton, G.G.AshtonAst, S.S.AstAston, S. M.S. M.AstonAstone, P.P.AstoneAufmuth, P.P.AufmuthAulbert, C.C.AulbertAylott, B. E.B. E.AylottBabak, S.S.BabakBaker, P. T.P. T.BakerBaldaccini, F.F.BaldacciniBallardin, G.G.BallardinBallmer, S. W.S. W.BallmerBarayoga, J. C.J. C.BarayogaBarbet, M.M.BarbetBarclay, S.S.BarclayBarish, B. C.B. C.BarishBarker, D.D.BarkerBarone, F.F.BaroneBarr, B.B.BarrBarsotti, L.L.BarsottiBarsuglia, M.M.BarsugliaBartlett, J.J.BartlettBarton, M. A.M. A.BartonBartos, I.I.BartosBassiri, R.R.BassiriBasti, A.A.BastiBatch, J. C.J. C.BatchBauer, Th S.Th S.BauerBaune, C.C.BauneBavigadda, V.V.BavigaddaBehnke, B.B.BehnkeBejger, M.M.BejgerBelczynski, C.C.BelczynskiBell, A. S.A. S.BellBell, C.C.BellBenacquista, M.M.BenacquistaBergman, J.J.BergmanBergmann, 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.BirchBiscans, S.S.BiscansBitossi, M.M.BitossiBiwer, C.C.BiwerBizouard, M. A.M. A.BizouardBlackburn, J. K.J. K.BlackburnBlackburn, L.L.BlackburnBlair, C. D.C. D.BlairBlair, D.D.BlairBloemen, S.S.BloemenBock, O.O.BockBodiya, T. P.T. P.BodiyaBoer, M.M.BoerBogaert, G.G.BogaertBojtos, P.P.BojtosBond, C.C.BondBondu, F.F.BonduBonelli, L.L.BonelliBonnand, R.R.BonnandBork, R.R.BorkBorn, M.M.BornBoschi, V.V.BoschiBose, SukantaSukantaBoseBradaschia, C.C.Bradaschia2025-08-302025-08-302015-01-2110.1103/PhysRevD.91.0220042-s2.0-84921530995https://d8.irins.org/handle/IITG2025/21496In this paper we present the results of a coherent narrow-band search for continuous gravitational-wave signals from the Crab and Vela pulsars conducted on Virgo VSR4 data. In order to take into account a possible small mismatch between the gravitational-wave frequency and two times the star rotation frequency, inferred from measurement of the electromagnetic pulse rate, a range of 0.02 Hz around two times the star rotational frequency has been searched for both the pulsars. No evidence for a signal has been found and 95% confidence level upper limits have been computed assuming both that polarization parameters are completely unknown and that they are known with some uncertainty, as derived from x-ray observations of the pulsar wind torii. For Vela the upper limits are comparable to the spin-down limit, computed assuming that all the observed spin-down is due to the emission of gravitational waves. For Crab the upper limits are about a factor of 2 below the spin-down limit, and represent a significant improvement with respect to past analysis. This is the first time the spin-down limit is significantly overcome in a narrow-band search.trueArticlehttp://link.aps.org/pdf/10.1103/PhysRevD.91.0220041550236821 January 201542022004arJournal41