TITLE: GCN CIRCULAR NUMBER: 6382 SUBJECT: GRB070412: MAGIC telescope GeV observation DATE: 07/05/07 17:05:18 GMT FROM: Markus Garczarczyk at MPI/MAGIC Galante N., Garczarczyk M., Gaug M., Scapin V., Bastieri D. and Longo F. report for the MAGIC collaboration: The MAGIC Imaging Atmospheric Cherenkov Telescope performed a follow-up observation of the SWIFT-BAT burst GRB070412 (GCN circular 6273, Romano P. et al.). We received the delayed GCN alert at T0+647s, The data taking with MAGIC started at T0+701s, 27s after the alert income. We observed the sky positon for 124min on April 12th and for further 178min on April 13th, starting at T0+7.6x10^4s. No evidence for VHE gamma-ray emission above the analysis threshold of 90 GeV was found in both data sets. 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) : 1.03 x 10^(-11) erg/cm^2/s E(125-175 GeV) : 0.31 x 10^(-11) erg/cm^2/s E(175-300 GeV) : 0.75 x 10^(-11) erg/cm^2/s E(300-1000 GeV) : 0.77 x 10^(-11) erg/cm^2/s The upper limits correspond to the time period between T0+701s and T0+8181s. We can also exclude emission of a constant flux during our observation in any 100s time bin higher than: E(80-200 GeV) : 2.2 x 10^(-9) erg/cm^2/s E(200-1000 GeV) : 0.5 x 10^(-9) erg/cm^2/s for the time period between T0+701s and T0+8181s, and: E(80-200 GeV) : 2.5 x 10^(-9) erg/cm^2/s E(200-1000 GeV) : 0.5 x 10^(-9) erg/cm^2/s for the time period between T0+7.6x10^4 s and T0+8.7x10^4 s. This message can be cited.