The New Gravitational-Wave Catalog Just Found Evidence of Black Holes Born From Other Black Holes

The Latest Gravitational-Wave Catalog

The LIGO-Virgo-KAGRA collaboration released its latest gravitational-wave catalog this year, and the numbers alone are striking: 161 newly confirmed detections, bringing the total ever recorded to 390. Buried in that update are a few outright records. Scientists narrowed the origin of one event, GW240615, down to an area covering just six square degrees of sky, the most precise localization ever achieved for a gravitational-wave source. They used another event, GW250114 — the loudest signal ever recorded — to test Stephen Hawking's black hole area theorem directly, and confirmed it held.

New Insights from Black Hole Mergers

Two black hole mergers, GW241011 and GW241110, were detected about a month apart in late 2024, and both showed an unusual signature in how the merging black holes were spinning, spins pointing in ways that don't match what you'd expect from two black holes that formed directly from collapsing stars. At the time, they read as anomalies. Researchers now think they are not anomalies at all. They are evidence that some black holes are second-generation, produced by an earlier black hole merger — one that merged and then collided again, most likely inside a dense, crowded stellar cluster where repeat collisions are more likely.

Analyzing the Scale of GWTC-5

What makes this a significant finding is its scale. GWTC-5 doesn't just add new events; it lets researchers analyze 267 sources together, including 104 new ones, and look for correlations across the whole set: which masses come with which spins, and whether those pairings fall into distinct groups. Black holes in different mass ranges show different spin patterns, consistent enough across the population that the two odd 2024 events stop looking like one-of-a-kind curiosities and start looking like the visible edge of a real, ongoing formation pathway. That's the actual shift GWTC-5 represents in gravitational-wave astronomy.

Research with Us

That population-versus-model comparison is exactly the work underway at the Gravitational Wave Paleontology Lab. Its active GROWL Catalog project is building the first large-scale, public catalog of gravitational-wave population-synthesis simulations, letting researchers systematically check observed sources like these against theoretical models instead of treating each simulation as its own isolated silo.

Community Research Opportunities

Rakiura's community research groups are built to go a step beyond typical citizen science: sustained, mentored co-production. Entry starts with conversation, not credentials; no academic affiliation required. From there, a roughly 8-week onboarding, backed by weekly office hours and structured materials, trains contributors in the lab's actual research tools and data-science techniques, preparing them to take on a real, open strand of the lab's work, mentored directly by the researcher who owns it, in this case, Floor Broekgaarden.

If a result like this second-generation black hole evidence is the kind of thing that makes you want to look at the data yourself, GROWL Catalog is where that door is currently open.