The twin detectors of the NSF’s Laser Interferometer Gravitational-Wave Observatory (LIGO) have made a groundbreaking discovery by detecting the highest composite mass recorded to date and the merger of two black holes. This event, identified as GW231123 and discovered on November 23, 2023, produced a final black hole with a mass over 225 times that of the Sun.
GW231123 An infographic detailing the merger of black holes. Image credits: Simona J. Miller/Caltech.
LIGO made history in 2015 with the first direct detection of gravitational waves, the ripples in spacetime.
In that instance, the waves were generated by the merger of black holes, culminating in a black hole with a mass 62 times that of our Sun.
The signal was simultaneously detected by LIGO’s twin detectors located in Livingston, Louisiana, and Hanford, Washington.
Since then, the LIGO team has collaborated with partners from Italy’s Virgo detectors and Japan’s KAGRA to create the LVK collaboration.
These detectors have collectively observed over 200 black hole mergers during their fourth observational run since starting in 2015.
Previously, the largest black hole merger recorded was in 2021 during the event GW190521, which had a total mass of 140 times that of the Sun.
During the GW231123 event, a black hole with a mass of 225 was formed by merging two black holes, one approximately 100 times and the other 140 times the mass of the Sun.
This discovery places it in a rare category known as intermediate mass black holes, which are heavier than those resulting from star collapses but significantly lighter than the supermassive black holes found at the centers of galaxies.
In addition to their substantial mass, these merged black holes exhibited rapid rotation.
“This is the largest black hole binary we’ve observed in gravitational waves and poses a significant challenge to our understanding of black hole formation,” stated Dr. Mark Hannam, an astrophysicist at Cardiff University and a member of the LVK collaboration.
“The existence of such a large black hole defies standard stellar evolution models.”
“One potential explanation is that the two black holes in this binary could have formed from the merger of smaller black holes.”
“This observation highlights how gravitational waves uniquely uncover the fundamental and exotic properties of black holes throughout the universe,” remarked Dr. Dave Reitze, executive director of LIGO at Caltech.
Researchers announced this week the discovery of GW231123, which will be discussed at the 24th International Conference on General Relativity and Gravity (GR24) and the 16th Edoardo Amaldi Meeting on Gravitational Waves, held jointly at the Gr-Amaldi Meeting in Glasgow, Scotland.
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LIGO-Virgo-KAGRA Collaboration. GW231123: The largest black hole binary detected by gravitational waves. Gr-Amaldi 2025
Source: www.sci.news
