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Hints for a GeV component in the emission from GRBs are known since the EGRETobservations during the '90s and they have been recently confirmed by the dataof the Fermi satellite. These results have, however, shown that a fullysatisfactory interpretative framework of the GRB phenomena is still lacking.The MAGIC telescope opens the possibility to extend the measurement of GRBs inthe several tens up to hundreds of GeV energy range. From the theoretical pointof view, both leptonic and hadronic processes have been suggested to explainthe possible GeV/TeV counterpart of GRBs. Observations with ground-basedtelescopes of very high energy photons (E>30 GeV) from these sources are goingto play a key role in discriminating among the different proposed emissionmechanisms which are barely distinguishable at lower energies. MAGIC telescopeobservations of the GRB090102 (z=1.547) field from 03:14:52 UT to 06:54:01 UTare analyzed to derive upper limits to the GeV/TeV emission. We compare theseresults to the expected emissions evaluated for different processes in theframework of the standard fireball model. The results we obtained arecompatible with the expected emission but cannot yet set further constraints onthe theoretical scenario. However, the difficulty in modeling the low energydata for this event makes it difficult to fix in an unambiguous way thephysical parameters which describe the fireball. Nonetheless, the MAGICtelescope, thanks to its low energy threshold and fast repositioning, isopening for the first time the possibility to fill the energy gap betweenspace-based gamma detectors and the ground-based measurements. This will makespossible GRBs multiwavelength studies in the very high energy domain.

MAGIC low energy observation of GRB090102 afterglow