Scientists collaborating under the LIGO‑Virgo‑KAGRA (LVK) network have identified the most massive black-hole merger ever recorded—an event so enormous that it challenges established astrophysical theories. Detected on November 23, 2023, and dubbed GW231123, this merger involved two black holes weighing approximately 100 and 140 times the mass of the Sun, producing a final black hole of around 225 M☉.What makes GW231123 particularly striking is that both progenitor black holes fall within the “forbidden mass gap” (roughly 60–130 M☉),a range where standard stellar collapse shouldn’t produce black holes.Furthermore, these massive bodies were spinning near the theoretical limits set by general relativity—adding complexity to the analysis.
The most plausible explanation is a hierarchical merger, where each black hole was itself the product of earlier collisions—offering a rare glimpse into how intermediate-mass black holes form in dense stellar environments. This breakthrough not only extends LIGO’s record but also opens a new avenue for gravitational-wave astronomy, with researchers gearing up to discuss GW231123 at conferences in Glasgow and refine models to decode its full implications