Cardiff researchers hail coming-of-age for gravitational wave astronomy as event catalogue nearly doubles
9 June 2026
A new expanded catalogue of gravitational wave events will offer astronomers unprecedented insights into the most energetic phenomena in the universe, according to a team of Cardiff University researchers.
The Gravitational Wave Transient Catalogue-5.0 (GWTC-5) documents all 390 gravitational wave events observed to date by the LIGO, verga and KAGRA observatories. It has nearly doubled in size with the addition of 161 events detected between April 2024 and the end of January 2025.
The Cardiff team, from the Gravity Exploration Institute, is part of a global network of astronomers already using this catalogue and carrying out work on the origins, properties and characteristics of these cosmic events.
Evidence for the existence of second-generation black holes, the most precise sky localisation ever achieved for a gravitational wave source, and the first measurement of three vibrational modes of a black hole have all been revealed among the events recorded in GWTC-5.
These new perspectives opened up by increased observations, hails a coming-of-age for gravitational wave astronomy, according to the international team.
Dr Vivien Raymond, a Reader in the Gravity Exploration Institute at Cardiff University, said: “Reaching 390 recorded events – nearly doubling previous counts – and identifying the loudest gravitational wave to date, this catalogue represents a significant milestone in the exploration of the most energetic phenomena in the universe.
“The expanded dataset enables more precise population studies of black holes and neutron stars, stronger constraints on their formation and evolution, and improved tests of fundamental physics, including general relativity.”
Together, these results lay the groundwork for increasingly powerful and detailed gravitational wave astronomy in the years ahead, and remind us that the universe still has many surprises left, if we keep listening closely.
Gravity Exploration Institute
One of the innovations that GWTC-5 has enabled is a new way of “hearing” cosmic events like the collision of black holes.
The technique, called astrophysical calibration, describes a process similar to the pitch-correction used in music production.
The team from the international LIGO, Virgo and Kagra (LVK) gravitational wave observatory collaboration, drew on Cardiff University expertise, and applied the technique to use gravitational-wave signals to measure the response of their incredibly sensitive instruments.
What is especially exciting about this work is that gravitational-wave signals can be used directly to calibrate our detectors — somewhat like a tuning fork that tells a musician whether their instrument is perfectly in tune.
“The waveform models describing black hole mergers are one of the great triumphs of modern theoretical physics, and tests of general relativity further confirm their accuracy with extraordinary confidence,” explains Parthapratim Mahapatra, a research associate in Cardiff University’s School of Physics and Astronomy and a co-author of the research.
“This means the signals themselves can serve as nature’s own tuning fork: when our detectors hear them slightly off-key, it may suggest that it is our instruments, not the universe, that need adjusting – allowing us to extract more from every detection while sharpening our tests of Einstein’s theory itself.”
The updated catalogue also reveals more about the origins of these phenomena.
Two very special black hole mergers were detected in October and November 2024, just one month apart.
Analysis of their characteristics, by an international team of researchers including Cardiff University PhD candidate Elizabeth Flanagan, indicates the objects could be ‘second-generation’ black holes, likely formed in very dense and crowded cosmic environments, such as stellar clusters, where black holes are more likely to collide and merge repeatedly.
Elizabeth Flanagan, a PhD researcher at Cardiff University, said: “With the rapidly increasing number of detections, we are beginning to see signs that black hole mergers do not all come from a single population.”
Some of the events in the latest catalogue show properties consistent with black holes that may have formed through previous mergers, giving us new clues about how these systems assemble and evolve across cosmic time.
Later this year, the LVK collaboration will release an updated version of the Gravitational Wave Transient Catalogue, further expanding the known population of black hole binaries.
They will also start a new observing run, offering the prospect of additional detections of gravitational waves from black hole mergers and potentially new types of astrophysical sources.
It’s remarkable that, in just the past decade, we have progressed from the first detection of gravitational waves to hundreds of observed events – with many more discoveries expected in the coming months and years.
Gravity Exploration Institute
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