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