B. Abbott, California Institute of Technology
R. Abbott, California Institute of Technology
R. Adhikari, California Institute of Technology
J. Agresti, California Institute of Technology
P. Ajith, Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
B. Allen, Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
R. Amin, Louisiana State University
S. B. Anderson, California Institute of Technology
W. G. Anderson, University of Wisconsin-Milwaukee
M. Arain, University of Florida
M. Araya, California Institute of Technology
H. Armandula, California Institute of Technology
M. Ashley, The Australian National University
S. Aston, University of Birmingham
P. Aufmuth, Gottfried Wilhelm Leibniz Universität Hannover
C. Aulbert, Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
S. Babak, Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
S. Ballmer, California Institute of Technology
H. Bantilan, Carleton College, USA
B. C. Barish, California Institute of Technology
C. Barker, LIGO Hanford
D. Barker, LIGO Hanford
B. Barr, University of Glasgow
P. Barriga, The University of Western Australia
M. A. Barton, University of Glasgow
K. Bayer, Massachusetts Institute of Technology
K. Belczynski, Northwestern University
J. Betzwieser, Massachusetts Institute of Technology
P. T. Beyersdorf, San Jose State University
B. Bhawal, California Institute of Technology
I. A. Bilenko, Lomonosov Moscow State University
Tiffany Z. Summerscales, Andrews UniversityFollow

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Publication Date



We have searched for gravitational waves (GWs) associated with the SGR 1806-20 hyperflare of 27 December 2004. This event, originating from a Galactic neutron star, displayed exceptional energetics. Recent investigations of the x-ray light curve's pulsating tail revealed the presence of quasiperiodic oscillations (QPOs) in the 30-2000 Hz frequency range, most of which coincides with the bandwidth of the LIGO detectors. These QPOs, with well-characterized frequencies, can plausibly be attributed to seismic modes of the neutron star which could emit GWs. Our search targeted potential quasimonochromatic GWs lasting for tens of seconds and emitted at the QPO frequencies. We have observed no candidate signals above a predetermined threshold, and our lowest upper limit was set by the 92.5 Hz QPO observed in the interval from 150 s to 260 s after the start of the flare. This bound corresponds to a (90% confidence) root-sum-squared amplitude hrss-det 90%=4.5×10-22strainHz-1/2 on the GW waveform strength in the detectable polarization state reaching our Hanford (WA) 4 km detector. We illustrate the astrophysical significance of the result via an estimated characteristic energy in GW emission that we would expect to be able to detect. The above result corresponds to 7.7×1046erg (=4.3×10-8M c2), which is of the same order as the total (isotropic) energy emitted in the electromagnetic spectrum. This result provides a means to probe the energy reservoir of the source with the best upper limit on the GW waveform strength published and represents the first broadband asteroseismology measurement using a GW detector. © 2007 The American Physical Society.

Journal Title

Physical Review D - Particles, Fields, Gravitation and Cosmology






First Department



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