Daily monitoring of scattered light noise due to microseismic variability at the Virgo interferometer

Understand

Data acquired by the Virgo interferometer during the second part of the O3 scientific run, referred to as O3b, were analysed with the aim of characterising the onset and time evolution of scattered light noise in connection with the variability of microseismic noise in the environment surrounding the detector.

• The adaptive algorithm used, called pytvfemd, is suitable for the analysis of time series which are both nonlinear and nonstationary.
• It allowed to obtain the first oscillatory mode of the differential arm motion degree of freedom of the detector during days affected by scattered light noise.
• The mode's envelope i.e., its instantaneous amplitude, is then correlated with the motion of the West end bench, a known source of scattered light during O3.