LIGO Livingston Interferometer. (Credit: Caltech/MIT/LIGO Lab)

Observatories and Collaborations

As an 'observatory', LIGO consists of two identical detectors (interferometers) separated by 3000 km. The LIGO Hanford Observatory (LHO) is situated in southeastern Washington State and the LIGO Livingston Observatory (LLO) is in rural Livingston, Louisiana. When both detectors are operating, they work in unison as a single observatory, though each can operate and even make detections (in some special cases) on its own.

LIGO is not the only gravitational wave observatory in the world. While LIGO's two detectors constitute a mini internal collaboration between LHO and LLO, an even larger gravitational wave observatory collaboration exists between LIGO and other detectors and researchers around the world, including Virgo in Italy and KAGRA in Japan. Data from LIGO, Virgo, and KAGRA are combined and analyzed jointly. This collaboration significantly enhances the search for gravitational waves.

To learn more about LIGO's two detectors and the broader, global gravitational wave research collaboration, click on the links below: