Allsky search for periodic gravitational waves in LIGO S4 data
Abstract
We report on an allsky search with the LIGO detectors for periodic gravitational waves in the frequency range 50 1000 Hz and with the frequency’s time derivative in the range 1×10^{8}Hzs^{1} to zero. Data from the fourth LIGO science run (S4) have been used in this search. Three different semicoherent methods of transforming and summing strain power from short Fourier transforms (SFTs) of the calibrated data have been used. The first, known as StackSlide, averages normalized power from each SFT. A “weighted Hough” scheme is also developed and used, which also allows for a multiinterferometer search. The third method, known as PowerFlux, is a variant of the StackSlide method in which the power is weighted before summing. In both the weighted Hough and PowerFlux methods, the weights are chosen according to the noise and detector antennapattern to maximize the signaltonoise ratio. The respective advantages and disadvantages of these methods are discussed. Observing no evidence of periodic gravitational radiation, we report upper limits; we interpret these as limits on this radiation from isolated rotating neutron stars. The best populationbased upper limit with 95% confidence on the gravitationalwave strain amplitude, found for simulated sources distributed isotropically across the sky and with isotropically distributed spin axes, is 4.28×10^{24} (near 140 Hz). Strict upper limits are also obtained for small patches on the sky for bestcase and worstcase inclinations of the spin axes.
 Publication:

Physical Review D
 Pub Date:
 January 2008
 DOI:
 10.1103/PhysRevD.77.022001
 arXiv:
 arXiv:0708.3818
 Bibcode:
 2008PhRvD..77b2001A
 Keywords:

 04.80.Nn;
 07.05.Kf;
 95.55.Ym;
 97.60.Gb;
 Gravitational wave detectors and experiments;
 Data analysis: algorithms and implementation;
 data management;
 Gravitational radiation detectors;
 mass spectrometers;
 and other instrumentation and techniques;
 Pulsars;
 General Relativity and Quantum Cosmology;
 Astrophysics
 EPrint:
 39 pages, 41 figures An error was found in the computation of the C parameter defined in equation 44 which led to its overestimate by 2^(1/4). The correct values for the multiinterferometer, H1 and L1 analyses are 9.2, 9.7, and 9.3, respectively. Figure 32 has been updated accordingly. None of the upper limits presented in the paper were affected