LIGO and Virgo Unveil Record Haul of 161 New Black Hole Collisions
On May 26, 2026, the LIGO-Virgo-KAGRA (LVK) collaboration released the most extensive gravitational-wave catalog ever published. Known as GWTC-5.0, it adds 161 new binary black hole mergers to the record books. The total number of confirmed gravitational-wave events now stands at 390. And among them is a signal so powerful it broke the loudness record by nearly a factor of two.
The catalog covers 9.5 months of observations from the fourth observing run, O4b, which ran from April 2024 through January 2025. During this period, the three advanced detectors at Hanford (Washington), Livingston (Louisiana), and Cascina (Italy) listened to the cosmos with improved sensitivity. They caught the ripples of spacetime from black hole pairs spiraling inward and colliding across the universe. In a statement accompanying the preprint, Leo Tsukada of the University of Nevada, Las Vegas called the results “a testament to the rapidly expanding reach of gravitational-wave astronomy.”
The headline event of GWTC-5.0 is GW250114, a binary black hole merger detected on January 14, 2025. Its signal-to-noise ratio (SNR) came in at 76.9, nearly doubling the previous record of 42.4 set by GW150914, the very first direct detection of gravitational waves in 2015. The event was so loud that it was visible as a clean waveform in the raw detector data without any filtering. “The signal basically jumped out of the screen,” noted Daniel Williams of the University of Glasgow in a media briefing. GW250114 involved two black holes of roughly 28 and 20 solar masses that merged into a final remnant of about 45 solar masses, at a distance of roughly 2.6 billion light-years.
Precision localization also reached new highs. The merger designated GW240615 delivered the best sky localization ever achieved for a gravitational-wave event, confined to a mere 6 square degrees on the sky. That is roughly the area covered by a thumbnail held at arm’s length. Such tight localization is crucial for follow-up observations with electromagnetic telescopes, though no counterpart was detected for this event.
Two other events stand out for what they reveal about black hole formation channels. GW241011 and GW241110 show properties consistent with hierarchical mergers, meaning black holes that are themselves the products of earlier black hole mergers. These second-generation black holes would be heavier than typical stellar-mass black holes and are expected to form in dense star clusters where repeated mergers can occur. “These are our best candidates yet for hierarchical black hole mergers,” said Ian Harry of the University of Portsmouth. “They help us distinguish between formation in isolated binaries and formation in dense dynamical environments.”
The catalog also includes the first clear measurement of three distinct ringdown modes from a single merged black hole. When two black holes collide, the final remnant settles into a stable shape by emitting a characteristic “ringdown” of gravitational waves. Each ringdown mode corresponds to a specific oscillation frequency determined by the remnant’s mass and spin. Detecting multiple modes tests the “no-hair theorem” of general relativity, which predicts that a black hole is fully described by just three parameters: mass, spin, and charge. The measurement is consistent with the predictions of Einstein’s theory, further confirming general relativity in the strong-field regime.
An intriguing pattern in the catalog is the complete absence of neutron star mergers. All 161 new events involve binary black holes. None contain neutron stars, the ultra-dense remains of supernova explosions whose mergers produce both gravitational waves and electromagnetic signals (as famously seen in GW170817). This is not entirely unexpected. Neutron star mergers are rarer than black hole mergers, and the improved sensitivity of O4b may still not be enough to catch them at the same rate. The LVK collaboration expects neutron star mergers to appear again in future runs.
Beyond individual events, GWTC-5.0 provides a sharper picture of the overall black hole population. The catalog improves constraints on the mass distribution of black holes, the rate at which they merge, and how those rates evolve with cosmic time. The data suggest that black hole mergers become more common as we look back to earlier epochs, peaking around a redshift of 2, when the universe was about 3 billion years old.
The catalog also delivers a new measurement of the Hubble constant, H₀, which describes the expansion rate of the universe. Using the “standard siren” method (where gravitational-wave signals provide a direct measure of distance independent of the cosmic distance ladder), the LVK collaboration now reports H₀ = 71.0 +9.0 -7.1 km/s/Mpc. This measurement improves on the precision from the previous catalog, GWTC-4.0, by 25.7%. It remains consistent with both the cosmic microwave background-based value from Planck (67.4 km/s/Mpc) and the supernova-based value from SH0ES (73.0 km/s/Mpc), without yet being precise enough to resolve the tension between them. “Every new catalog brings us closer to settling the Hubble constant debate,” said Marie Anne Bizouard of the Virgo Collaboration and CNRS.
What comes next? The LVK collaboration is now preparing for O5, the fifth observing run, which will push sensitivity even further. When O5 begins, the detection rate is expected to rise to several events per day. New detectors are also joining the network: KAGRA in Japan has recently joined routine observations, and LIGO India is expected to come online later this decade. A larger detector network means better sky localization and more events with multiple detectors.
For now, GWTC-5.0 stands as the most comprehensive catalog of cosmic collisions ever assembled. It captures the sounds of black holes ringing across the universe, and with them, the story of how the heaviest objects in the cosmos grow and evolve.
Source: GWTC-5.0: The Fifth LIGO-Virgo-KAGRA Gravitational-Wave Transient Catalog of Compact Binary Mergers. arXiv:2605.27225 [gr-qc]. Submitted to The Astrophysical Journal Letters, May 2026.