All-sky search for periodic gravitational waves in LIGO S5 the full data

We report on an all-sky search for periodic gravitational waves in the frequency band 50-800 Hz and with the frequency time derivative in the range of 0 through -6 x 10(-9) Hz/s. Such a signal could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. After recent improvements in the search program that yielded a 10x increase in computational efficiency, we have searched in two years of data collected during LIGO's fifth science run and have obtained the most sensitive all-sky upper limits on gravitational-wave strain to date. Near 150 Hz our upper limit on worst-case linearly polarized strain amplitude h(0) is 1 x 10(-24), while at the high end of our frequency range we achieve a worst-case upper limit of 3.8 x 10(-24) for all polarizations and sky locations. These results constitute a factor of 2 improvement upon previously published data. A new detection pipeline utilizing a loosely coherent algorithm was able to follow up weaker outliers, increasing the volume of space where signals can be detected by a factor of 10, but has not revealed any gravitational-wave signals. The pipeline has been tested for robustness with respect to deviations from the model of an isolated neutron star, such as caused by a low-mass or long-period binary companion. RI Hammond, Giles/A-8168-2012; Freise, Andreas/F-8892-2011; Marchesoni, Fabio/A-1920-2008; Strain, Kenneth/D-5236-2011; Cella, Giancarlo/A-9946-2012; Vocca, Helios/F-1444-2010; Bell, Angus/E-7312-2011; Acernese, Fausto/E-4989-2010; Toncelli, Alessandra/A-5352-2012; Gammaitoni, Luca/B-5375-2009; Shaddock, Daniel/A-7534-2011; Khalili, Farit/D-8113-2012; Prato, Mirko/D-8531-2012; Gemme, Gianluca/C-7233-2008; Hild, Stefan/A-3864-2010; Ferrante, Isidoro/F-1017-2012; prodi, giovanni/B-4398-2010; Santamaria, Lucia/A-7269-2012; Costa, Cesar/G-7588-2012; Prokhorov, Leonid/I-2953-2012; Gorodetsky, Michael/C-5938-2008; Punturo, Michele/I-3995-2012