{
  "bibcode": "2006GCN..5623....1S",
  "body": "A. Stefanescu, F. Schrey, S. Duscha, G. Kanbach, M. Muehlegger, N.\nPrimak, H. Steinle (MPE Garching) of the OPTIMA-Burst Team report the\nfollowing:\n\nWe have observed the OT of GRB 060926 under unfavorable weather \nconditions until it became unobservable at ~18:40 UT. To make \ncomparision easier with GCN 5618 (U. Kiziloglu et al.), we have \ncallibrated our observations against the R2-magnitudes of 4 nearby \nUSNO-B1 stars (1030-0324059, 1030-0324042, 1030-0324039, 1030-0324046). \nWe estimate the magnitude of the OT as follows:\n\n    t-t_BAT        exp-time\n[min] (mid-exp)     [s]         R_mag\n-----------------------------------------------\n    35.4             600         20.3 +-0.5\n    59.7             600         20.6 +-0.5\n    72.7             600         20.7 +-0.7\n    90.7             2x 1200     21.0 +-0.7\n    101.2            1200        21.1 +-0.7\n\n\nWe fitted these values with a powerlaw with a decay index of 0.73 +-0.1.\nThis is significantly shallower than the powerlaw between the MASTER \nobservations (GCN 5619, V. Lipunov et al.) and ours, with a decay index \nof 0.90 +-0.06 - allthough this could be due to incompatibilities in \nzero-point.\n\nWe thank J. Papamastorakis of the University of Crete and his team for \nthe possibility to use the 1.3m Telescope at Skinakas Observatory for a \nprolonged period of time.",
  "circularId": 5623,
  "createdOn": 1159317602000,
  "email": "astefan@mpe.mpg.de",
  "subject": "GRB 060926: OPTIMA-Burst -- further observations",
  "submitter": "Alexander Stefanescu at MPE  <astefan@mpe.mpg.de>",
  "eventId": "GRB 060926"
}