Validating gravitational-wave detections: The Advanced LIGO hardware injection system

Understand

Hardware injections are simulated gravitational-wave signals added to the Laser Interferometer Gravitational-wave Observatory (LIGO).

• The detectors' test masses are physically displaced by an actuator in order to simulate the effects of a gravitational wave.
• The simulated signal initiates a control-system response which mimics that of a true gravitational wave.
• This provides an end-to-end test of LIGO's ability to observe gravitational waves.