128 New Gravitational-Wave Signals Redefine Black Hole Demographics
The LVK collaboration released Gravitational-Wave Transient Catalog 4.0 (GWTC-4), adding 128 new gravitational-wave candidates detected from 2015–2024, more than doubling the catalog. The expanded set reveals a wider variety of black-hole binaries, including very massive and rapidly spinning systems, enabling tests of general relativity and new measurements of the universe’s expansion (via the Hubble constant). This growth pushes gravitational-wave astronomy into new regions of parameter space and promises deeper insights into black-hole formation and cosmic evolution.
