End benches scattered light modeling and subtraction in Advanced Virgo

TL;DR

This paper presents a detailed model and subtraction method for scattered light noise from the Advanced Virgo end benches, improving data quality and enabling optical calibration of the detector strain data.

Contribution

It introduces a detailed scattered light noise model and demonstrates its effectiveness in noise subtraction and optical calibration during gravitational wave detection.

Findings

Effective subtraction of scattered light noise using auxiliary channels

Model parameters enable optical characterization of the interferometer

Provides a novel method for absolute calibration of strain data

Abstract

Advanced Virgo end benches were a significant source of scattered light noise during the third observing run that lasted from April 1 2019 until March 27 2020. We describe how that noise could be subtracted using auxiliary channels during the online strain data reconstruction. We model in detail the scattered light noise coupling and demonstrate that further noise subtraction can be achieved. We also show that the fitted model parameters can be used to optically characterized the interferometer and in particular provide a novel way of establishing an absolute calibration of the detector strain data.