{
  "bibcode": "2012GCN.13228....1T",
  "body": "P. J. Tristram (MJUO), A. Fukui (NAOJ/OAO) and T. Sako (Nagoya U.) \nreport on behalf of the MOA collaboration.\n\nWe began prompt observations for the afterglow of GRB120404A (Stratta et al., GCN 13208)\nat Apr. 4 12:55:44 UT (4.7 min after the Swift trigger 519380),\nusing the 61-cm B&C telescope at Mt John University Observatory in New Zealand.\nWe obtained a series of I and V band images with 60 sec exposure times, followed by some \n120 and 180 sec exposures, until 18:04 UT (5.2 hours after the trigger).\n\nIn the first images, we detected marginal objects having I ~ 18.6 and V ~ 19.0 \nat the reported coordinate of the afterglow (Osborne et al., GCN13218).\nThe afterglow was then getting bright, as reported by Breeveld et al. (GCN 13226),\nreaching I = 16.6 and V = 17.4 at around 13:40 UT (about 50 min after the trigger).\nAfter the peak, the afterglow had faded out with the rate of +0.7 mag/hour.\nThe characteristic magnitudes are summarized as bellow.\n\n  UT              I                        V\n-------------------------------------------------------\n12:56   18.6 +2/-0.6      19.0 +1.2/-0.6\n13:40   16.6 +/- 0.1        17.4 +/- 0.1\n16.50   18.4 +0.6/-0.4    19.5 +0.6/-0.4\n-------------------------------------------------------\n\nAll the above magnitudes are measured on 60-sec exposure images,\nand calibrated by the GSC2.3 star catalog.\nThe errors represent 1-sigma statistic uncertainties.\n\n\nWe would like to thank Alberto J Castro-Tirado for giving us useful suggestions.\nWe acknowledge University of Canterbury for allowing the use of the B&C telescope.",
  "circularId": 13228,
  "createdOn": 1333638551000,
  "email": "afukui@stelab.nagoya-u.ac.jp",
  "subject": "GRB120404A: MOA optical observations of the initial rise afterglow",
  "submitter": "Akihiko Fukui at Nagoya U/MOA  <afukui@stelab.nagoya-u.ac.jp>",
  "eventId": "GRB 120404A"
}