Upper limit map of a background of gravitational waves

B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S.B. Anderson, W.G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B.C. BarishC. Barker, D. Barker, B. Barr, P. Barriga, M.A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P.T. Beyersdorf, B. Bhawal, I.A. Bilenko, G. Billingsley, R. Biswas, E. Black, K. Blackburn, L. Blackburn, D. Blair, B. Bland, J. Bogenstahl, L. Bogue, R. Bork, V. Boschi, S. Bose, P.R. Brady, V.B. Braginsky, J.E. Brau, M. Brinkmann, A. Brooks, D.A. Brown, A. Bullington, S. Hild

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Abstract

We searched for an anisotropic background of gravitational waves using data from the LIGO S4 science run and a method that is optimized for point sources. This is appropriate if, for example, the gravitational wave background is dominated by a small number of distinct astrophysical sources. No signal was seen. Upper limit maps were produced assuming two different power laws for the source strain power spectrum. For an f(-3) power law and using the 50 Hz to 1.8 kHz band the upper limits on the source strain power spectrum vary between 1.2 x 10(-48) Hz(-1) (100 Hz/f)(3) and 1.2 x 10(-47) Hz(-1) (100 Hz/f)(3), depending on the position in the sky. Similarly, in the case of constant strain power spectrum, the upper limits vary between 8.5 x 10(-49) Hz(-1) and 6.1 x 10(-48) Hz(-1). As a side product a limit on an isotropic background of gravitational waves was also obtained. All limits are at the 90% confidence level. Finally, as an application, we focused on the direction of Sco-X1, the brightest low-mass x-ray binary. We compare the upper limit on strain amplitude obtained by this method to expectations based on the x-ray flux from Sco-X1.
Original languageEnglish
Article number082003
Number of pages11
JournalPhysical Review D
Volume76
Issue number8
DOIs
Publication statusPublished - 1 Oct 2007
Externally publishedYes

Keywords

  • RADIATION

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