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 x 10(-50) strain(2) Hz(-1) and 5 - 35 x 10(-49) strain(2) 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 approximate to 7 - 10(-25) in the most sensitive frequency range near 160 Hz.
- LIGO S5
- gravitational waves
- stochastic analysis
Abadie, J., Lockerbie, N. A., Tokmakov, K. V., LIGO Scientific Collaboration, & Virgo Collaboration (2011). Directional limits on persistent gravitational waves using LIGO S5 science data. Physical Review Letters, 107(27), [271102 ]. https://doi.org/10.1103/PhysRevLett.107.271102