{
  "bibcode": "2006GCN..5789....1G",
  "body": "Gaug M. and Garczarczyk M., Bastieri D., Fagiolini M., Galante N.,\nLongo F., Mizobuchi S., Piccioli A., Scapin V. and Stamerra A.\nreport for the MAGIC collaboration:\n\nThe MAGIC Imaging Atmospheric Cherenkov Telescope performed a follow-up\nobservation of the SWIFT-BAT burst GRB061028 (GCN circular 5762, Sakamoto\nT. et al.). We received the GCN alert at T0+140s. The telescope slewed\nimmediately to the GRB sky coordinates and started data taking 29s after\nthe alert, at T0+169s. Due to the long time delay of the alert and the\nburst duration of T90=106s, only the early afterglow phase could be\nobserved by MAGIC. Our observation window covered the weak tail emission\nmeasured by BAT and the X-ray afterglow measured by XRT (Sakamoto T. et\nal.). The observation continued for 100min.\n\nNo evidence for VHE gamma-ray emission above the analysis threshold of\n110GeV was found. A preliminary analysis, for the hypothesis of steady\nemission and assumption of a differential photon spectral index of -2.5,\nyields the following 95% CL differential flux upper limits (inc. 30%\nsystematic error on the absolute flux level):\n\nE(100-125 GeV)  : 1.6 x 10^(-10) erg/cm^2/s\nE(125-175 GeV)  : 0.8 x 10^(-10) erg/cm^2/s\nE(175-300 GeV)  : 0.7 x 10^(-10) erg/cm^2/s\nE(300-1000 GeV) : 0.3 x 10^(-10) erg/cm^2/s\n\nThe upper limits apply of the time window between T0+169s and T0+1969s\n(the first 30min of the MAGIC data sample).\n\nThis message can be cited.",
  "circularId": 5789,
  "createdOn": 1162986341000,
  "email": "garcz@mppmu.mpg.de",
  "subject": "GRB061028: MAGIC telescope GeV observation",
  "submitter": "Markus Garczarczyk at MPI/MAGIC  <garcz@mppmu.mpg.de>",
  "eventId": "GRB 061028"
}