Overview of KAGRA: Calibration, detector characterization, physical environmental monitors, and the geophysics interferometer

TL;DR

This paper provides an overview of KAGRA's calibration, detector characterization, environmental monitoring, and geophysics systems, essential for gravitational wave detection and data quality assessment in the upcoming astronomy era.

Contribution

It introduces the calibration methods, detector characterization, and environmental monitoring systems implemented in KAGRA, highlighting their roles in gravitational wave data analysis.

Findings

Calibration method for gravitational wave signals

Characterization of detector performance

Environmental monitors for data quality evaluation

Abstract

KAGRA is a newly built gravitational wave observatory, a laser interferometer with a 3 km arm length, located in Kamioka, Gifu, Japan. In this series of articles, we present an overview of the baseline KAGRA, for which we finished installing the designed configuration in 2019. This article describes the method of calibration (CAL) used for reconstructing gravitational wave signals from the detector outputs, as well as the characterization of the detector (DET). We also review the physical environmental monitors (PEM) system and the geophysics interferometer (GIF). Both are used for characterizing and evaluating the data quality of the gravitational wave channel. They play important roles in utilizing the detector output for gravitational wave searches. These characterization investigations will be even more important in the near future, once gravitational wave detection has been achieved, and in using KAGRA in the gravitational wave astronomy era.