{
  "bibcode": "2009GCN..8816....1G",
  "body": "Gaug M. (IAC Tenerife), Antonelli L. A. (INAF Rome),\nBastieri D. (Univ. Padova), Becerra J. G. (IAC Tenerife),\nCarosi A. (INAF Rome), Covino S. (INAF Rome), Galante N. (MPI Munich), \nGarczarczyk M. (IFAE Barcelona), La Barbera A. (INAF Palermo),\nLongo F. (INFN Trieste), Persic M. (Univ. Udine), Scapin V. (Univ. Udine), \nand Teshima M. (MPI Munich) for the MAGIC collaboration\n\nThe MAGIC Imaging Atmospheric Cherenkov Telescope performed a follow-up\nobservation of GRB090102 (Mangano et al., circular 8762). We started data \ntaking with MAGIC at 03:14:52 UT under excellent observation conditions. \nThe observation continued for 13149 s.\n\nNo evidence for VHE gamma-ray emission above a (preliminary) analysis \nthreshold of 89 GeV was found.\n\nA preliminary analysis, for the hypothesis of steady emission and \nassumption of a differential photon spectral index of -2.5, yields the \nfollowing 95% CL differential flux upper limits, including a 30% \nsystematic uncertainty on the telescope efficiency. (Because of the \nchanging telescope sensitivities due to different zenith angle ranges \nduring the observation of GRB090102, the data sample was split into\n5 parts):\n\nE (  80- 125 GeV): 2.30 * 10^-10 erg/cm^2/s\nE ( 125- 175 GeV): 1.61 * 10^-10 erg/cm^2/s\nE ( 175- 300 GeV): 0.34 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV): 0.04 * 10^-10 erg/cm^2/s\nfor a time window from 03:14:01 UT to 04:21:01 UT\n\nE (  80- 125 GeV): 1.12 * 10^-10 erg/cm^2/s\nE ( 125- 175 GeV): 0.50 * 10^-10 erg/cm^2/s\nE ( 175- 300 GeV): 0.20 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV): 0.07 * 10^-10 erg/cm^2/s\nfor a time window from 04:21:01 UT to 05:31:00 UT\n\nE ( 125- 175 GeV): 1.02 * 10^-10 erg/cm^2/s\nE ( 175- 300 GeV): 0.30 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV): 0.20 * 10^-10 erg/cm^2/s\nfor a time window from 05:39:00 UT to 06:02:00 UT\n\nE ( 125- 175 GeV): 2.40 * 10^-10 erg/cm^2/s\nE ( 175- 300 GeV): 0.49 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV): 0.25 * 10^-10 erg/cm^2/s\nfor a time window from 06:02:00 UT to 06:25:00 UT\n\nE ( 175- 300 GeV): 0.40 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV): 0.11 * 10^-10 erg/cm^2/s\nfor a time window from 06:25:00 UT to 07:02:00 UT\n\nWe can also exclude emission of a constant flux in any 100s time bin \nsmaller than:\n\nE (  80- 125 GeV): 12.58 * 10^-10 erg/cm^2/s\nE ( 125- 175 GeV):  7.53 * 10^-10 erg/cm^2/s\nE ( 175- 300 GeV):  3.27 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV):  1.41 * 10^-10 erg/cm^2/s\nfor a time window from 03:14:01 UT to 04:21:01 UT\n\nE (  80- 125 GeV): 18.16 * 10^-10 erg/cm^2/s\nE ( 125- 175 GeV): 15.56 * 10^-10 erg/cm^2/s\nE ( 175- 300 GeV):  3.46 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV):  1.40 * 10^-10 erg/cm^2/s\nfor a time window from 04:21:01 UT to 05:31:00 UT\n\nE ( 125- 175 GeV): 11.61 * 10^-10 erg/cm^2/s\nE ( 175- 300 GeV):  2.47 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV):  0.91 * 10^-10 erg/cm^2/s\nfor a time window from 05:39:00 UT to 06:02:00 UT\n\nE ( 125- 175 GeV): 12.38 * 10^-10 erg/cm^2/s\nE ( 175- 300 GeV):  5.38 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV):  1.53 * 10^-10 erg/cm^2/s\nfor a time window from 06:02:00 UT to 06:25:00 UT\n\nE ( 175- 300 GeV): 10.06 * 10^-10 erg/cm^2/s\nE ( 300-1000 GeV):  1.28 * 10^-10 erg/cm^2/s\nfor a time window from 06:25:00 UT to 07:02:00 UT\n\nFurther analysis, exploiting the recently upgraded event trigger, is still \nunderway for energies below 80 GeV.\n\nThis message can be cited.",
  "circularId": 8816,
  "createdOn": 1232108202000,
  "email": "garcz@mppmu.mpg.de",
  "subject": "GRB090102: MAGIC telescope GeV observation",
  "submitter": "Markus Garczarczyk at MPI/MAGIC  <garcz@mppmu.mpg.de>",
  "eventId": "GRB 090102"
}