First Observational Results of GEO600 and LIGO

The LIGO and GEO detectors have come online and have performed their first science runs. The data from the four detectors is analysed jointly by teams of scientists based in Germany, UK, and the US [1-5]. The AEI leads the efforts to search for gravitational wave signals emitted by rapidly rotating neutron stars. While developing hierarchical techniques to perform blind searches, the team has set the first direct upper limits on the emission of gravitational waves from a set of isolated known pulsars using radio-guided phase templates [6]. Due to the unprecedented sensitivity of the detectors for the four closest pulsars the gravitational strain upper limits translate into upper limits on the equatorial ellipticity of the objects that are smaller than 10^-5.

The upper curves of the figure show the characteristic gravitational wave amplitudes detectable from a known source with a 1% false alarm rate and 10% false dismissal rate.
The lower curve shows the LIGO design sensitivity for 1 year of data.
The stars represent the upper limits found in [6] for 28 known pulsars.
The circles are the spindown upper limits for the pulsars with negative spindown values if all the measured rotational energy loss were due to gravitational waves and assuming a moment of inertia of 10⁴⁵ g.cm².

Bibliography

[1] B. Abbott et al. (The LIGO Scientific Collaboration), Detector Description and Performance for the First Coincidence Observations between LIGO and GEO, Nucl. Instrum. Meth. A 517/1-3 (2004) 154 – 179
Eprint: gr-qc/0308043

[2] B. Abbott et al. (The LIGO Scientific Collaboration), Setting upper limits on the strength of periodic gravitational waves from PSR J1939 + 2134 using the first science data from the GEO600 and LIGO detectors, Phys. Rev. D 69 (2004) 082004
Eprint: gr-qc/0308050

[3] B. Abbott et al. (The LIGO Scientific Collaboration), Analysis of LIGO data for gravitational waves from binary neutron stars, Phys. Rev. D 69 (2004) 122001
Eprint: gr-qc/0308069

[4] B. Abbott et al. (The LIGO Scientific Collaboration), Upper limits on the strength of periodic gravitational waves from PSR J1939+2134, Class. Quantum Grav. 21 (2004) S671 – S676
Eprint: gr-qc/0311023

[5] B. Abbott et al. (The LIGO Scientific Collaboration), Analysis of LIGO Data for Stochastic Gravitational Waves, Phys. Rev. D 69 (2004) 122004
Eprint: gr-qc/0312088

[6] B. Abbott et al. (The LIGO Scientific Collaboration), Limits on gravitational wave emission from selected pulsars using LIGO data, Phys.Rev.Lett. 94 (2005) 181103
Eprint: gr-qc/0410007

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