Abbott, B.Abbott, R.Adhikari, R.Ajith, P.Allen, B.Allen, G.Amin, R.Anderson, S.Anderson, W.Arain, M.Araya, M.Armandula, H.Armor, P.Aso, Y.Aston, S.Aufmuth, P.Aulbert, C.Babak, S.Baker, P.Ballmer, S.et al.2009-10-272009-10-272009Physical Review Letters, 2009; 102(11):111102-01-111102-060031-90071079-7114http://hdl.handle.net/2440/51448We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50–1100 Hz and with the frequency’s time derivative in the range -5×10⁻⁹–0  Hz s⁻¹. Data from the first eight months of the fifth LIGO science run (S5) have been used in this search, which is based on a semicoherent method (PowerFlux) of summing strain power. Observing no evidence of periodic gravitational radiation, we report 95% confidence-level upper limits on radiation emitted by any unknown isolated rotating neutron stars within the search range. Strain limits below 10⁻²⁴ are obtained over a 200-Hz band, and the sensitivity improvement over previous searches increases the spatial volume sampled by an average factor of about 100 over the entire search band. For a neutron star with nominal equatorial ellipticity of 10⁻⁶, the search is sensitive to distances as great as 500 pc.en©2009 American Physical SocietyGeneral Relativity and Quantum Cosmology (gr-qc)Astrophysics (astro-ph)Journal article002009039710.1103/PhysRevLett.102.1111020002643802000132-s2.0-6354908787739123Ottaway, D. [0000-0001-6794-1591]Veitch, P. [0000-0002-2597-435X]