TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5571 SUBJECT: GRB060825: MAGIC telescope GeV observation DATE: 06/09/13 19:34:57 GMT FROM: Markus Garczarczyk at MPI/MAGIC Gaug M. and Garczarczyk M., Bastieri D., Fagiolini M., Galante N., Longo F., Mizobuchi S., Picciolini A., Scampin V. and Stamerra A. report for the MAGIC collaboration: The MAGIC Imaging Atmospheric Cherenkov Telescope performed a follow-up observation of the SWIFT-BAT burst GRB060825 (GCN circular 5478, Fenimore E. et al.). We received the GCN alert at T0+19s. The telescope slewed fast to the GRB sky coordinates and started data taking 38s after the alert, at T0+57s. In total 33min of data from the GRB sky coordinates were accumulated. Due to the short duration of the burst (T90 = 8.8s), only the early afterglow phase was observed. The observation overlapped with the small x-ray flare detected by SWIFT-XRT (GCN circular 5479, Beardmore A.P. et al.), centered at T0+220s. No evidence for VHE emission above the analysis threshold of 90GeV was found. A preliminary analysis, for the hypothesis of steady emission and assumption of a differential photon spectral index of -2.5, yields the following 95% CL differential flux upper limits (inc. 30% systematic error on the absolute flux level): E(80-125 GeV) : 1.8 x 10^(-10) erg/cm^2/s E(125-175 GeV) : 1.9 x 10^(-10) erg/cm^2/s E(175-300 GeV) : 1.2 x 10^(-10) erg/cm^2/s E(300-1000 GeV) : 0.6 x 10^(-10) erg/cm^2/s This message can be cited.