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Physical Sciences and Mathematics Commons

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Astrophysics and Astronomy

2007

Andrews University

Articles 1 - 6 of 6

Full-Text Articles in Physical Sciences and Mathematics

Upper Limit Map Of A Background Of Gravitational Waves, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales Oct 2007

Upper Limit Map Of A Background Of Gravitational Waves, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales

Faculty Publications

We searched for an anisotropic background of gravitational waves using data from the LIGO S4 science run and a method that is optimized for point sources. This is appropriate if, for example, the gravitational wave background is dominated by a small number of distinct astrophysical sources. No signal was seen. Upper limit maps were produced assuming two different power laws for the source strain power spectrum. For an f-3 power law and using the 50 Hz to 1.8 kHz band the upper limits on the source strain power spectrum vary between 1.2×10-48Hz-1 (100Hz/f)3 and 1.2×10-47Hz-1 (100Hz/f)3, depending on the position …


Searches For Periodic Gravitational Waves From Unknown Isolated Sources And Scorpius X-1: Results From The Second Ligo Science Run, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, S. J. Berukoff, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, Tiffany Z. Summerscales Oct 2007

Searches For Periodic Gravitational Waves From Unknown Isolated Sources And Scorpius X-1: Results From The Second Ligo Science Run, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, S. J. Berukoff, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, Tiffany Z. Summerscales

Faculty Publications

We carry out two searches for periodic gravitational waves using the most sensitive few hours of data from the second LIGO science run. Both searches exploit fully coherent matched filtering and cover wide areas of parameter space, an innovation over previous analyses which requires considerable algorithm development and computational power. The first search is targeted at isolated, previously unknown neutron stars, covers the entire sky in the frequency band 160-728.8 Hz, and assumes a frequency derivative of less than 4×10-10Hz/s. The second search targets the accreting neutron star in the low-mass x-ray binary Scorpius X-1 and covers the frequency bands …


Search For Gravitational Wave Radiation Associated With The Pulsating Tail Of The Sgr 1806-20 Hyperflare Of 27 December 2004 Using Ligo, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales Sep 2007

Search For Gravitational Wave Radiation Associated With The Pulsating Tail Of The Sgr 1806-20 Hyperflare Of 27 December 2004 Using Ligo, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales

Faculty Publications

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 …


Upper Limits On Gravitational Wave Emission From 78 Radio Pulsars, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales Aug 2007

Upper Limits On Gravitational Wave Emission From 78 Radio Pulsars, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales

Faculty Publications

We present upper limits on the gravitational wave emission from 78 radio pulsars based on data from the third and fourth science runs of the LIGO and GEO 600 gravitational wave detectors. The data from both runs have been combined coherently to maximize sensitivity. For the first time, pulsars within binary (or multiple) systems have been included in the search by taking into account the signal modulation due to their orbits. Our upper limits are therefore the first measured for 56 of these pulsars. For the remaining 22, our results improve on previous upper limits by up to a factor …


First Cross-Correlation Analysis Of Interferometric And Resonant-Bar Gravitational-Wave Data For Stochastic Backgrounds, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales Jul 2007

First Cross-Correlation Analysis Of Interferometric And Resonant-Bar Gravitational-Wave Data For Stochastic Backgrounds, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales

Faculty Publications

Data from the LIGO Livingston interferometer and the ALLEGRO resonant-bar detector, taken during LIGO's fourth science run, were examined for cross correlations indicative of a stochastic gravitational-wave background in the frequency range 850-950 Hz, with most of the sensitivity arising between 905 and 925 Hz. ALLEGRO was operated in three different orientations during the experiment to modulate the relative sign of gravitational-wave and environmental correlations. No statistically significant correlations were seen in any of the orientations, and the results were used to set a Bayesian 90% confidence level upper limit of Ωgw(f)≤1.02, which corresponds to a gravitational-wave strain at 915 …


Search For Gravitational-Wave Bursts In Ligo Data From The Fourth Science Run, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales Jan 2007

Search For Gravitational-Wave Bursts In Ligo Data From The Fourth Science Run, B. Abbott, R. Abbott, R. Adhikari, J. Agresti, P. Ajith, B. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. Arain, M. Araya, H. Armandula, M. Ashley, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, K. Bayer, K. Belczynski, J. Betzwieser, P. T. Beyersdorf, B. Bhawal, I. A. Bilenko, Tiffany Z. Summerscales

Faculty Publications

The fourth science run of the LIGO and GEO 600 gravitational-wave detectors, carried out in early 2005, collected data with significantly lower noise than previous science runs. We report on a search for short-duration gravitational-wave bursts with arbitrary waveform in the 64-1600 Hz frequency range appearing in all three LIGO interferometers. Signal consistency tests, data quality cuts and auxiliary-channel vetoes are applied to reduce the rate of spurious triggers. No gravitational-wave signals are detected in 15.5 days of live observation time; we set a frequentist upper limit of 0.15 day-1 (at 90% confidence level) on the rate of bursts with …