LIGO-Virgo-KAGRA Catalog Doubles Gravitational-Wave Detections

The LIGO-Virgo-KAGRA collaboration has published the fourth edition of its gravitational-wave catalog, expanding the record of cosmic events detected between May 2023 and January 2024. This update more than doubles the number of known gravitational-wave candidates compared to previous releases.

With the addition of 128 new candidates, the catalog now documents approximately 218 gravitational-wave events with high astrophysical probability. The expanded dataset includes a range of black hole binary systems and two black hole-neutron star mergers observed during the first part of the fourth observing run.

Several notable detections are featured in the new catalog. One event, GW231123_135430, stands out as the heaviest black hole binary observed to date, with both components estimated at around 130 times the mass of the Sun. Another event, GW231028_153006, involves black holes with inspiral spins reaching about 40 percent of the speed of light.

The catalog also records GW231118_005626, an unusually uneven black hole binary system where one black hole is roughly twice as massive as its companion. These varied discoveries provide new data for studying the properties and formation of compact object binaries.

What the numbers show

• GWTC-4 adds 128 new gravitational-wave candidates
• The catalog now contains about 218 high-probability events
• Heaviest black hole binary detected: ~130 solar masses per component
• Black hole spins observed up to 40% the speed of light
• New Hubble constant estimate: ~76 km/s/Mpc

Researchers used the expanded catalog to calculate a new independent estimate of the Hubble constant, arriving at a value of approximately 76 kilometers per second per megaparsec. This measurement contributes to ongoing efforts to refine the rate at which the universe is expanding.

The catalog’s data also support tests of general relativity. For example, the gravitational-wave signal GW230814_230901 was analyzed and found to remain consistent with the predictions of Einstein’s theory during strong-field conditions.

The LIGO-Virgo-KAGRA collaboration stated that the new catalog enables further investigation into the diversity of gravitational-wave sources. The inclusion of rare and extreme systems allows for more detailed studies of astrophysical processes involving black holes and neutron stars.

By documenting a wider variety of gravitational-wave events, the GWTC-4 release provides a foundation for future research and helps refine measurements of fundamental cosmic parameters.

* This article is based on publicly available information at the time of writing.