Fermi GBM detected a likely long GRB (GRB 261020A) on Oct 20, 2026 at 05:37:08 UT

AI Summary

Fermi GBM triggered on a likely long gamma-ray burst at 05:37:08 UT on October 20, 2026 (trigger 814167433). The burst was localized to RA = 284.4°, Dec = -33.9° (J2000) with a 2.5° statistical uncertainty, though the source lay 86° from the Fermi LAT boresight. Multiple ground-processed positions refined the localization over ~9 minutes with burst significance ranging from 16.4 to 21σ in the 44–280 keV band. However, a flight-based classification algorithm assigned 93% probability to AGN origin with only 4% to GRB, introducing ambiguity about the true nature of this transient.

Measurements

Notices (1)

Fermi GBM — GRB · Tue, 20 Oct 2026 05:37:08 GMT

GCN Circulars (1)

GCN-45992 — GRB 261020A · Tue, 20 Oct 2026 05:47:46 GMT
The Fermi Gamma-ray Burst Monitor (GBM) detected a likely long gamma-ray burst (GRB 261020A) on October 20, 2026, at 05:37:08 UT. The event was located at RA = 284.4, Dec = -33.9 (J2000 degrees) with a statistical uncertainty of 2.5 degrees, and the angle from the Fermi LAT boresight is 86.0 degrees.