Reducing Scattered Light in LIGO's Third Observing Run

Understand

Noise due to scattered light has been a frequent disturbance in the Advanced LIGO gravitational wave detectors, hindering the detection of gravitational waves.

• The non stationary scatter noise caused by low frequency motion can be recognized as arches in the time-frequency plane of the gravitational wave channel.
• In this paper, we characterize the scattering noise for LIGO's third observing run O3 from April, 2019 to March, 2020.
• We find at least two different populations of scattering noise and we investigate the multiple origins of one of them as well as its mitigation.