Calibration of Advanced Virgo and reconstruction of detector strain h(t) during the Observing Run O3

Understand

The three Advanced Virgo and LIGO gravitational wave detectors participated to the third observing run (O3) between 1 April 2019 15:00 UTC and 27 March 2020 17:00 UTC,leading to several gravitational wave detections per month.

• This paper describes the Advanced Virgo detector calibration and the reconstruction of the detector strain $h(t)$ during O3, as well as the estimation of the associated uncertainties.
• For the first time, the photon calibration technique as been used as reference for Virgo calibration, which allowed to cross-calibrate the strain amplitude of the Virgo and LIGO detectors.
• The previous reference, so-called free swinging Michelson technique, has still been used but as an independent cross-check.