Timing system of LIGO discoveries

The Advanced LIGO timing system

Gravitational wave detection using a network of detectors relies upon the precise time stamping of gravitational wave signals. The relative arrival times between detectors are crucial, e.g. in recovering the source direction, an essential step in using gravitational waves for multi-messenger astronomy. Due to the large size of gravitational wave detectors, timing at different parts of a given d...

LIGO Sensing System Performance

GW150914: The Advanced LIGO Detectors in the Era of First Discoveries.

Following a major upgrade, the two advanced detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) held their first observation run between September 2015 and January 2016. With a strain sensitivity of 10^{-23}/sqrt[Hz] at 100 Hz, the product of observable volume and measurement time exceeded that of all previous runs within the first 16 days of coincident observation. On S...

The LIGO Interferometer Sensing and Control System {*}

The LIGO Interferometer Sensing and Control System (ISC) is a large and highly distributed Multiple Input Multiple Output (MIMO) control system that is used to control the length and alignment degrees of freedom of the interferometers. The 4 kilometer FabryPerot cavity lengths are controlled to better than 10 meters (rms) and the angular degrees of freedom are controlled to better than 10 radia...

The Ligo Suspended Optic Digital Control System

The original LIGO suspension control system [1] used analog circuitry to implement the closed loop damping required for local control of each of the suspended optics. As installation and commissioning activities have progressed, it has become apparent that these controls do not provide the performance and flexibility that will be required for operation of the interferometers. Recent development...