Modernizing calibration monitoring for low-latency, high-fidelity calibration of Advanced LIGO

With the operation of advanced ground-based gravitational-wave detectors, such as Advanced LIGO, Advanced Virgo, and KAGRA, we now have nearly 200 confident detections of gravitational-waves from merging compact binary systems. The calibration of the interferometric detectors in low-latency enables low-latency detection and electromagnetic follow-up of gravitational-wave candidates. Historically, the low-latency calibrated strain data from Advanced LIGO was used for detection but not for final publication. O4 marked the first time the low-latency calibrated strain data was available for final publication due to the availability of low-latency uncertainty estimation.
One component that enabled the low-latency uncertainty estimation of calibrated strain data in O4 was the development of CalMonitor, the real-time monitoring system for calibrated LIGO data. In preparation for the next observing run, we are modernizing the low-latency calibration pipeline, allowing for better integration of calibration monitoring. By computing and storing a variety of calibration metrics displayed in real time, we can quickly detect any errors or changes in calibration. Additionally, we work toward building real-time improvements to the calibrated strain data derived from the computed metrics. These advancements will improve the accuracy and robustness of the low-latency calibrated strain data, in turn improving the science outcomes derived from gravitational-wave detections.