What it is
GW250114, a gravitational-wave signal from two coalescing black holes of near-equal mass (33.6 and 32.2 solar masses), was observed by the two LIGO detectors with a network matched-filter signal-to-noise ratio of 80. The black holes carried small spins (0.26 at 90% credibility) and negligible eccentricity (0.03). Postmerger data are consistent with the dominant quadrupolar mode of a Kerr black hole and its first overtone, with the modes' frequencies constrained to ±30% of the Kerr spectrum. Analyses that exclude up to five of the strongest merger cycles confirm the remnant horizon area exceeds the sum of the two initial areas, testing Hawking's area law.
Why it matters
The area law (the second law of black hole mechanics) and the expectation that the remnant is a Kerr black hole are core predictions of general relativity, and this event tests both from a single signal. The postmerger data match the Kerr quadrupolar mode and its first overtone with frequencies held to ±30% of the Kerr spectrum, and the total horizon area is shown to exceed the sum of the two initial areas to high credibility even after excluding up to five of the strongest merger cycles.
Underlined numbers link to their source. Every metric and quoted figure is listed under Sources and data below.
Filed undergravitational waves, black holes, general relativity, ligo, hawking area law