18 dic 2025 - 18:06 CET

La Palma, Spain — The international CTAO LST Collaboration released remarkable findings from observations of GRB 221009A—the brightest gamma-ray burst (GRB) ever recorded. The results were published on 23 July by the renowned journal The Astrophysical Journal Letters (ApJ Letters). The publication presents in-depth observations conducted in 2022 with the Large-Sized Telescope (LST) prototype, the LST-1, during its commissioning phase at the Roque de los Muchachos Observatory on the CTAO-North site in La Palma, Spain. The observations revealed a hint of an excess in the gamma-ray flux, which help provide new insights into the enigmatic and complex nature of GRBs at very high energies. The results support theoretical models in which these bursts generate structured, multi-layered jets where particles are accelerated.