Flux upper limit of gamma-ray emission by GRB050713a from MAGIC Telescope observations

– 2 –ABSTRACTThe long-duration GRB050713a was observed by the MAGIC Telescope, 40seconds after the burst onset, and followed up for 37 minutes, until twilight. Theobservation, triggered by a SWIFT alert, covered energies above ≈ 175 GeV.Using standard MAGIC analysis, no evidence for a gamma signal was found. Asthe redshift of the GRBwas not measured directly, the flux upper limit, estimatedby MAGIC, is still compatible with the assumption of an unbroken power-lawspectrum extending from a few hundred keV to our energy range.Subject headings: gamma rays: bursts — gamma rays: observations