The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2−20×10−50 strain2 Hz−1 and 5−35×10−49 strain2 Hz−1 sr−1 for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets including Sco X-1, SN 1987A and the Galactic center as low as ≈7×10−25 in the most sensitive frequency range near 160 Hz.
Abadie, J., “Directional Limits on Persistent Gravitational Waves Using LIGO S5 Science Data.” Physical Review Letters, vol. 107, no. 27, American Physical Society, Dec. 2011, p. 271102, doi:10.1103/PhysRevLett.107.271102.
Physical Review Letters