English: MECHANISM OF GAMMA-RAY BURSTS

https://earthsky.org/space/jan-14-2019-gamma-ray-burst-brightest-so-far

What are gamma ray bursts? They are cosmic explosions, with radiation up to a trillion times the energy of visible light. This illustration shows the set-up for the most common type of gamma ray burst. The core of a massive star (left) has collapsed and formed a black hole. This “engine” drives a jet of particles that moves through the collapsing star and out into space at nearly the speed of light. The prompt emission, which typically lasts a minute or less, may arise from the jet’s interaction with gas near the newborn black hole and from collisions between shells of fast-moving gas within the jet (internal shock waves). The afterglow emission occurs as the leading edge of the jet sweeps up its surroundings (creating an external shock wave) and emits radiation across the spectrum for some time — months to years, in the case of radio and visible light, and many hours at the highest gamma-ray energies yet observed. These far exceed 100 billion electron volts (GeV) for two recent GRBs.