GW Astrophysics

What are we looking for?

Location of the Source

Interferometers are sensitive to Gravitational Waves from all directions and we can't point them at a specific part of the sky like a telescope. However, by using several instruments at different places on the Earth we can reconstruct the location of a source in the sky Gravitational Waves are predicted to travel at the speed of light, which means there will be a time delay between the signal detection in the separate interferometers. We can use the time of arrival of the signal at each detector to localise the direction to the Gravitational Wave source. We currently use a network of three Gravitational Wave detectors in the LIGO-Virgo collaboration. The two USA based LIGO detectors are in Hanford, Washington and Livingston, Louisiana. The Virgo detector is located near Pisa in Italy. We can see how the relative timing of the detection in each interferometer is affected by the direction the wave is coming from in the animations below. The following animations are silent and the incoming wave has been slowed by a factor of 100..

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