15 research outputs found
Search for gravitational wave bursts in LIGO's third science run
We report on a search for gravitational wave bursts in data from the three
LIGO interferometric detectors during their third science run. The search
targets subsecond bursts in the frequency range 100-1100 Hz for which no
waveform model is assumed, and has a sensitivity in terms of the
root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No
gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published
in Classical and Quantum Gravit
Upper limits from the LIGO and TAMA detectors on the rate of gravitational-wave bursts
We report on the first joint search for gravitational waves by the TAMA and LIGO collaborations. We looked for millisecond-duration unmodelled gravitational-wave bursts in 473 hr of coincident data collected during early 2003. No candidate signals were found. We set an upper limit of 0.12 events per day on the rate of detectable gravitational-wave bursts, at 90% confidence level. From simulations, we estimate that our detector network was sensitive to bursts with root-sum-square strain amplitude above approximately 1-3Ă—10 in the frequency band 700-2000 Hz. We describe the details of this collaborative search, with particular emphasis on its advantages and disadvantages compared to searches by LIGO and TAMA separately using the same data. Benefits include a lower background and longer observation time, at some cost in sensitivity and bandwidth. We also demonstrate techniques for performing coincidence searches with a heterogeneous network of detectors with different noise spectra and orientations. These techniques include using coordinated signal injections to estimate the network sensitivity, and tuning the analysis to maximize the sensitivity and the livetime, subject to constraints on the background
Hydraulic External Pre-Isolator System for LIGO
The Hydraulic External Pre-Isolator (HEPI) is the first 6 degrees of freedom
active seismic isolation system implemented at the Laser Interferometer
Gravitational Wave Observatory (LIGO). Implementation was first completed at
the LIGO Livingston Observatory (LLO) prior to LIGO's 5th science run,
successfully cutting down the disturbance seen by LLO's suspended optics in the
two most prominent seismic disturbance bands, the microseism (0.1-0.3Hz) and
the anthropogenic (1-3Hz) bands, by a factor of a few to tens. The improvement
in seismic isolation contributed directly to LLO's much improved duty cycle of
66.7% and LIGO's triple coincident duty cycle of 53%. We report the design,
control scheme, and isolation performance of HEPI at LLO in this paper. Aided
with this success, funding for incorporating HEPI into the LIGO Hanford
Observatory was approved and installation is currently underway.Comment: This paper has been withdrawn by the author due to revision
Upper limits on a stochastic background of gravitational waves
The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of ?0<8.4Ă—10-4 in the 69 156 Hz band is Ëś105 times lower than the previous result in this frequency range