O4b Open Data Release

First published: May 26, 2026

The LIGO, Virgo, and KAGRA collaborations have publicly released a new dataset from the second segment of their fourth observing run (O4b), covering gravitational-wave (GW) observations from April 10, 2024, to January 28, 2025. This release includes GW measurements recorded with unprecedented precision, with a detection range of roughly 165 Mpc (550 million light-years) for binary neutron star mergers and several thousand Mpc (a few billion light-years) for binary black hole mergers.

Unlike the first segment of O4, when only LIGO collected data, in O4b, Virgo joined the two LIGO observatories (Hanford and Livingston), allowing this data release to include strain data from all three interferometers. Additionally, the release provides several auxiliary channels for all three instruments.

In our pages, users can also explore the fifth version of the Gravitational Wave Transient Catalog (GWTC). This cumulative catalog includes events from previous observing runs, those identified in O4b data, and updated analysis results from O4a. The latest update to the GWTC catalog raises the total number of candidates more likely to be of astrophysical origin to 390.

For more information

• O4b Open Data publication page
• O4b Open Data Science Summary
• GWTC-5.0 catalog publication page
• GWTC-5.0 catalog Science Summary