Dr. Francesco Di Renzo

The LIGO-Virgo-KAGRA (LVK) collaboration recently concluded its fourth observing run, O4, the longest to date at two and a half years. O4 produced a massive dataset and numerous transient gravitational-wave alerts for low-latency multimessenger astronomy. Results from the first part, O4a, are summarized in the fourth Gravitational-Wave Transient Catalog (GWTC-4), which includes over 200 confident detections. Analysis of O4b and O4c data is ongoing. These achievements stem from significant improvements in detector performance and careful data characterization, which ensure robust inference of gravitational-wave signals. This presentation will highlight the latest scientific results from O4, detailing how detector upgrades and rigorous data characterization strengthened confidence in our published findings. The speaker will also describe the framework enabling the LVK Collaboration to deliver vetted, accurate alerts in low latency.