Although TeV emission in GRB afterglows had been predicted in some theoretical studies, it had remained observationally elusive for a long time, despite numerous searches at TeV energies over the past decades with various instruments, including MAGIC. MAGIC detection made GRB 190114C the Rosetta stone of gamma-ray bursts. The energies observed with MAGIC are much higher than what can be expected from synchrotron radiation. This process was enough to explain the afterglow emission previously observed from GRBs. The MAGIC data reaching TeV energies together with the very comprehensive MWL data, provided the first unequivocal evidence for an additional, distinct emission process in the afterglow. The most likely origin of the TeV emission is the inverse Compton process, where a population of photons are significantly kicked up in energy by colliding with high energy electrons. The additional component shows that the GRB explosions are even more powerful than thought before.
The analysis and interpretation in the multiwavelength context was led inside MAGIC by E. Moretti.