New Delhi: The international LIGO-Virgo-KAGRA (LVK) Collaboration has published its fifth Gravitational Wave Transient Catalogue (GWTC-5.0), introducing
161 newly confirmed gravitational wave detections between 10 April 2024 and 28 January 2025, captured during the O4b observation run. The update brings the total gravitational wave detections so far to 390 validated merger events since observations commenced in 2015. The expanded dataset establishes a foundation for high-precision statistical astronomy, population studies and cosmic expansion measurements. The fourth observing run alone now represents approximately 75 per cent of all historical detections, a surge that was driven by the systematic hardware upgrades to the detectors that allowed the observatories to detect three to four signals every week.
The twin LIGO facilities in the United States, the Virgo detector in Italy and the KAGRA consortium in Japan all collaborated on the detection and analysis of the data. The return of the Virgo detector to active service in April 2024 allowed researchers to triangulate locations in the sky through independent measurements, reducing the directional uncertainty to a few square degrees. The collaboration was able to pinpoint the merger of two black holes designated as GW240615, to an area of six square degrees. The precise localisation aids astronomers hunting for corresponding electromagnetic signals.
A number of papers published
Another event, designated as GW250114 recorded a signal-to-noise ration of 76.9, generated by two colliding black holes containing 32 and 34 solar masses. The clarity of the signal allowed scientists to test general relativity, and confirmed Stephen Hawking’s black hole area theorem regarding the expansion of the event horizon. The LVK collaboration also provided the first direct evidence for second-generation black holes, with a pair of signals, GW241011 and GW241110. Statistical analysis of 267 sources confirmed distinct sub-groups within the black hole populations based on correlations between mass, spin and distance, indicating multiple cosmic formation pathways. The remaining data from the fourth observation run is scheduled for public release in December.
