Facilities
A Nation-Wide Research Facility
The United States National Science Foundation Laser Interferometer Gravitational-wave Observatory (LIGO) laboratory comprises four facilities across the U.S.: two gravitational wave detectors (the interferometers) and two university research centers. The interferometers are situated 3,002 km (1,865 miles) apart, in Washington State (LIGO Hanford) and Louisiana (LIGO Livingston), while the two primary research centers are located at the California Institute of Technology (Caltech) in Pasadena, California, and the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts.
LIGO Livingston's corner station. Each arm extends 4 km (2.5 mi.) from this building. (Credit: Caltech/MIT/LIGO Lab/W. Katzman)
LIGO Hanford's X-arm stretches off into the Washington desert. (Credit: Kim Fetrow)
About 40 people work full-time at each detector site in Hanford, Washington and Livingston, Louisiana, including engineers, technicians, scientists, education and public outreach staff, and administrative and business personnel.
When observing, each detector collects its own data, which is compared in real time with that streaming from the other detector. Though this simultaneous observing is ideal, especially to help localize the source on the sky, coordinated operation it is no longer necessary for LIGO to confirm the arrival of a GW. In the event that weather or some technical conditions preclude one detector from operating, after many years of understanding what GW signals look like in our output data, LIGO's analysis pipelines and tools are now capable of recognizing a detection from a single instrument. Indeed, single-detector detections have become routine. That said, operating in a coordinated manner was critical for LIGO's ability to claim its first ever direct detection of gravitational waves.
As major academic and research institutions with world-class laboratories and facilities, Caltech and MIT are the home bases for many LIGO engineers who research and test ways to improve LIGO's sensitivity and stability, and the physicists and astrophysicists who strive to understand the properties of the phenomena that generate gravitational waves. These critical tasks are ongoing and evolving as LIGO and other astronomers and scientists continue to learn about and refine our understanding of the universe.
To learn more about why LIGO built two widely-separated detectors, visit LIGO's Dual Detectors.
