Gravitational-wave Detections Double With New Catalog

Scientists detect 128 new gravitational-wave candidates, including the heaviest black hole binary and other unusual signals.

Mar. 12, 2026 at 6:38am

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An international team of scientists, including Northwestern University astrophysicists, has detected 128 new gravitational-wave candidates - more than doubling the size of the current catalog. The new dataset includes the heaviest black hole binary detected to date, a binary where both black holes have exceptionally high spins, and an unusually lopsided pair of black holes. The catalog also holds two black hole-neutron star binaries.

Why it matters

Each new gravitational-wave detection adds another data point to our map of the universe's most extreme objects. As the catalog grows, scientists are beginning to see patterns emerge that help them understand how black holes and neutron stars form, evolve and merge throughout the cosmos.

The details

Scientists detected these ripples in space-time with a global network of gravitational-wave observatories: the U.S.-based National Science Foundation Laser Interferometer Gravitational-Wave Observatory (NSF LIGO), the Virgo interferometer in Italy and the Kamioka Gravitational Wave Detector (KAGRA) in Japan. The latest compilation of gravitational-wave detections will appear in a forthcoming special issue of The Astrophysical Journal Letters.

  • The observatories' fourth and most recent observing run took place between May 2023 and January 2024.

The players

Vicky Kalogera

A senior member of the LIGO Scientific Collaboration (LSC), the Daniel I. Linzer Distinguished University Professor of Physics and Astronomy at Northwestern's Weinberg College of Arts and Sciences, director of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and the NSF-Simons National AI Institute for the Sky (SkAI Institute).

Darsh Bellie

An NSF Graduate Research Fellow in physics and astronomy at Weinberg, who helped analyze the astrophysical implications of the most massive binary black hole merger in GWTC-4.

Debatri Chattopadhyay

A postdoctoral associate at CIERA, who was a member of the core writing team and co-led the writing of the paper's summary.

Shanika Galaudage

A CIERA-Adler postdoctoral fellow, who contributed to the population analysis for GWTC-4 and helped review the analyses in the scientific paper.

Ish Gupta

An N3AS postdoctoral fellow at CIERA, who used the updated sample of events to test Albert Einstein's theory of general relativity and helped estimate the parameters that characterize binary systems.

Anarya Ray

A CIERA postdoctoral fellow, who helped analyze candidate signals to determine the probability that each one came from a real astrophysical event and worked on population studies that reveal patterns among merging black holes and neutron stars.

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What they’re saying

“Each new gravitational-wave detection adds another data point to our map of the universe's most extreme objects. As our catalog grows, we're beginning to move from individual discoveries to seeing patterns begin to emerge. Those patterns are helping us understand how black holes and neutron stars form, evolve and merge throughout the cosmos.”

— Vicky Kalogera, Senior member of the LIGO Scientific Collaboration (LSC), Daniel I. Linzer Distinguished University Professor of Physics and Astronomy at Northwestern

What’s next

Scientists will use these new detections to start making connections about the properties of black holes as a population and to gauge how fast the universe is expanding, which remains a long-enduring mystery in cosmology.

The takeaway

The growing catalog of gravitational-wave detections is allowing scientists to move beyond individual discoveries and start to see patterns emerge that are helping them better understand the formation, evolution and merger of the most extreme objects in the universe, including black holes and neutron stars.