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17:00
Gamma-ray bursts are the biggest explosions in our Universe since the Big Bang: In just a few seconds, they release as much energy as the Sun will radiate over its entire lifetime. Even though they occur in far-away galaxies, their emission dominates the high-energy astrophysical sky during their seconds-long duration. They come from the cataclysmic deaths of very massive stars or the mergers of two compact objects such as neutron stars and black holes. In both cases the energy is concentrated in an astrophysical jet moving at approximately the speed of light. In October 2022, a once-in-a-lifetime gamma-ray burst smashed records and was dubbed the ‘Brightest of All Time,’ or the BOAT. In fact, it was so bright that it oversaturated the most sensitive gamma-ray burst monitors, posing a challenge for data reconstruction and analysis. But why was it so bright? And how long do we have to wait until the next one?
Using the BOAT as an example, we will give an introduction about the fascinating phenomena called gamma-ray bursts. From their accidental discovery during the Cold War to our still surprisingly limited understanding of their nature. The talk will revisit the state-of-the-art of theoretical modelling/interpretations (how are jets launched? what produces the gamma rays?), as well as current detector techniques (how do we catch a gamma-ray photon on Earth or in space?). Naturally, we will also discuss what we really learn from prominent, outstanding events such as the BOAT -- and the questions that still give scientists headaches.