The Laser Interferometer Gravitational-Wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new Bayesian 90% upper limit is Î©GW Ã— [H0/(12 km s-1 Mpc-1)]2 < 6.5 Ã— 10-5. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss the complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background. Â© 2007. The American Astronumical Society. All rights reserved.
B. Abbott, et. al., (2007) Searching for a stochastic background of gravitational waves with the laser interferometer gravitational-wave observatory.Astrophysical Journal659:2 I918. DOI: http://doi.org/10.1086/511329