New discoveries from the international network of scientists were enabled by four gravitational wave detectors – the twin detectors of the U.S. National Science Foundation Laser Interferometer Gravitational-wave Observatory (LIGO), one called Virgo supported by the European Gravitational Observatory and one called KAGRA in Japan’s Institute for Cosmic Ray Research. Since the previous data release from LIGO-Virgo-Kagra (LVK), detector upgrades have allowed for increasing sensitivity and led to extraordinary growth in the number of gravitational waves being found. Scientists had never detected the long-predicted ripples in spacetime a dozen years ago, but now members of the collaboration can find multiple gravitational waves in a given week. The latest observing run found a total of 161 gravitational waves, detected between April 2024 and the end of January 2025, bringing the total number of gravitational wave signals detected since the first discovery in 2015 to 390.
“The extraordinary sensitivity of our detectors now allows us to capture three or four gravitational wave signals every week,” said Ed Porter, researcher at the Laboratoire Astroparticule et Cosmologie of France’s National Centre for Scientific Research. “This ever-growing wealth of data, which an entire community of scientists and astronomers is working to analyze and study, has taken us from the era of initial discoveries into that of precision gravitational astronomy. Today, gravitational wave studies make possible analyses that were previously unimaginable: investigations into black hole populations, increasingly precise tests of general relativity under the extreme physical conditions of the phenomena we observe and the development of new methods to obtain ever more accurate estimates of the Hubble constant. It is a scenario that not many people would have bet on just 10 years ago.”
Improvements in the LKV’s ability to localize events, along with the increase in the size of the dataset, were key for the better estimate of the Hubble constant. Using the new dataset, the LVK collaboration obtained a new, independent measurement of the Hubble constant, which is just over 25% more precise than the estimate coming from the previous catalog release. This value is consistent with long-established measurements from both our cosmic neighborhood and the early universe but is not yet precise enough to resolve the tension between those measurements.
Several members of UT’s Center for Gravitational Physics participated in the collaboration’s latest observing run. Another UT physicist, Aaron Zimmerman, chaired the editorial board for the various papers submitted by the collaboration to Astrophysical Journal and Astrophysical Journal Letters.
The new catalog includes several detections that are themselves exceptional and sets new records in gravitational-wave astronomy observations: the best sky localization ever achieved for a gravitational wave source, the clearest gravitational wave signal ever recorded and evidence for the existence of second-generation black holes.
Adapted from a release by the European Gravitational Observatory.