Abbott, TAcernese, FAdams, CAdams, TAllen, BAnderson, WGBarone, FBartos, IBasti, ABertolini, ABlair, David GeraldBrau, J EBulten, H.J.Charlton, PhilipChow, JongChristensen, NCoward, DDhurandhar, SFactourovich, MFairhurst, SFrei, ZFrolov, VGenin, EGiaime, JGreenhalgh, R. J. S.Gustafson, RIyer, B RKawabe, KeitaLandry, MMandic, V.Mansell, GeorgiaMcClelland, DavidMeadors, G.D.Melatos, AndrewMendell, GMueller, GuidoMunch, JesperNguyen, ThanhOttaway, D JOwen, BenjaminPenn, SRajalakshmi, GRabeling, DavidReed, C MReitze, DRiles, KSammut, LSathyaprakash, BSaulson, PSavage, RSchofield, RScott, Susan MSengupta, Anand SShaddock, DanielSigg, DSintes, ASlagmolen, BramSouradeep, TStaley, ASummerscales, T.Z.Tanner, D BUnnikrishnan, C SVan Den Brand, J.Veitch, Peter JohnVocca, HVorvick, CWade, AndrewWard, RobertWen, LWhiting, B F2016-06-141550-7998http://hdl.handle.net/1885/102634We present results of a search for continuously emitted gravitational radiation, directed at the brightest low-mass x-ray binary, Scorpius X-1. Our semicoherent analysis covers 10 days of LIGO S5 data ranging from 50-550 Hz, and performs an incoherent sum of coherent F-statistic power distributed amongst frequency-modulated orbital sidebands. All candidates not removed at the veto stage were found to be consistent with noise at a 1% false alarm rate. We present Bayesian 95% confidence upper limits on gravitational-wave strain amplitude using two different prior distributions: a standard one, with no a priori assumptions about the orientation of Scorpius X-1; and an angle-restricted one, using a prior derived from electromagnetic observations. Median strain upper limits of 1.3×10-24 and 8×10-25 are reported at 150 Hz for the standard and angle-restricted searches respectively. This proof-of-principle analysis was limited to a short observation time by unknown effects of accretion on the intrinsic spin frequency of the neutron star, but improves upon previous upper limits by factors of ∼1.4 for the standard, and 2.3 for the angle-restricted search at the sensitive region of the detector.201510.1103/PhysRevD.91.0620082016-06-14