Description
The fourth observing run (O4) of the LIGO–Virgo–KAGRA (LVK) collaboration has opened a new phase in gravitational-wave astronomy, combining extended observing time with improved detector sensitivity. The O4a dataset, released as GWTC-4, includes over 200 confident detections and significantly enhances constraints on compact object populations. Further analyses of O4b and O4c are in progress. This contribution reviews the latest results from O4, focusing on how advances in detector technology and data characterization translate into improved gravitational-wave measurements. We discuss key developments in noise mitigation, data quality, and analysis pipelines, and their impact on detection confidence and astrophysical interpretation.
Author
Francesco Di Renzo
(University of Florence, Italy)