An international team from China and Italy has reported a possible cosmic encore to the landmark 2017 multi-messenger discovery. In November 2024, the LIGO-Virgo-KAGRA observatories detected gravitational waves from a binary black hole merger, designated S241125n. Remarkably, just seconds later, satellites recorded a short gamma-ray burst (GRB) from the same region of the sky.
Typically, binary black hole mergers are not expected to produce electromagnetic counterparts. S241125n could be a very rare gravitational-wave event that has been linked to a GRB across multiple wavelengths, extending multi-messenger astronomy into a new regime. Although the association is not yet definitive and will require further follow-up, the probability of a chance coincidence appears low, making the result statistically intriguing while warranting caution.
