LIGO-G050248-00-W

Report on LIGO Science Run S4

Fred Raab

On behalf of LIGO Scientific Collaboration

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Science Run 4 (S4) Description

• 22Feb05 18:00:00UTC to 24Mar05 06:00:00UTC• Duration of 708 hrs• Coordinated run:

» LIGO Hanford 4-km (H1) interferometer, Washington, USA

» LIGO Hanford 2-km (H2) interferometer, Washington, USA

» LIGO Livingston 4-km (L1) interferometer, Louisiana, USA

» GEO600 0.6-km interferometer, Hannover, Germany

» Allegro resonant-bar detector, Louisiana, USA

» Auriga resonant-bar detector, Legnaro, Italy

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LIGO (Washington) LIGO (Louisiana)

LIGO Detector Description

Funded by the National Science Foundation; operated by Caltech and MIT; the research focus for more than 500 LIGO Science Collaboration members worldwide.

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Basic Signature of Gravitational Waves for All Detectors

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Recycling Mirror

Optical

Cavity

4 km or2-1/2

miles

Beam Splitter

Laser

Photodetector

Fabry-Perot-Michelson with Power Recycling

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Clean Science Duty Cycle (segments > 300 seconds)

H1: 80.5% H2: 81.4%

L1: 74.5%

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Interferometer Strain Sensitivity

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Stability

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S4 Analysis Underway

• Bursts• Inspirals• Periodic• Stochastic

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Up Next…

• Approach closer to design goal sensitivity» Increase laser power to close shot-noise gap above 150 Hz» Improve thermal compensation of mirror figure» Improve RF oscillator phase stability» Improve rejection of line harmonics, especially near expected Crab

Pulsar frequency» Improve acoustic isolation, especially for H1, H2 pair (important for

stochastic search)» Improve alignment stability» Improve robustness against upconversion noise

• Commence S5 and accumulate one year of science data

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LIGO Search Papers(as of 9May05)

S1: “Setting upper limits on the strength of periodic gravitational waves using the first science data from the GEO600 and LIGO detectors”,Phys. Rev. D 69, 082004 (2004)

“First upper limits from LIGO on gravitational wave bursts”,Phys. Rev. D 69, 102001 (2004)

“Analysis of LIGO data for gravitational waves from binary neutron stars”, Phys. Rev. D 69, 122001 (2004)

“Analysis of first LIGO science data for stochastic gravitational waves”, Phys. Rev. D 69, 122004 (2004)

S2: “Limits on gravitational wave emission from selected pulsars using LIGO data”, Phys. Rev. Lett. 94, 181103 (2005).

“A search for gravitational waves associated with the gamma ray burst GRB030329 using the LIGO detectors”, gr-qc/0501068

“Upper limits on gravitational wave bursts from LIGO’s second science run”, gr-qc/0505029