{
  "bibcode": "2017GCN.20580....1K",
  "body": "A. Klotz, D. Turpin (IRAP-CNRS-OMP),\nD. Macpherson (UWA/ICRAR), D. Coward (UWA),\nM. Boer, R. Laugier (UNS-CNRS-OCA),\nGendre B. (UVI - Etelman Obs.),\nA. Williams (PO-UWA), R. Martin (PO-UWA)\nreport:\n\nWe imaged the field of GRB 170202A detected by SWIFT\n(trigger 736407) with the Zadko robotic telescope (D=100cm)\nlocated at the observatory - Gingin, Australia.\n\nThe observations started 58s after the GRB trigger\n(42s after the notice). The elevation of the field decreased from\n51 degrees above horizon and weather conditions\nwere very good.\n\nThe first image is trailed with a duration of 60.0s\n(see the description in Klotz et al., 2006, A&A 451, L39).\nWe detect the optical transcient described by Racusin et\nal. (GCNC 20575), Xin et al. (GCNC 20576) and Lipunov et\nal. (GCNC 20578). We calibrated magnitudes using the same\nreference star than Xin et al. (GCNC 20576).\n\nThe afterglow increases slowly and continuously from 73s\n(i.e. the limiting magnitude R~19) until 400s (R=16.5).\nAfter 550s the flux start to decrease with a standard\ntemporal decay alpha=-1 until 5000s (R=19).\n\nExtrapolation with this rate gives R=22.3 at t0+1day.\nSo we encourage to perform spectrometry.\n\nN.B. Zadko Magnitudes are not corrected for galactic dust extinction.",
  "circularId": 20580,
  "createdOn": 1486076117000,
  "email": "Alain.Klotz@free.fr",
  "subject": "GRB 170202A: Zadko observatory - Gingin optical observations",
  "submitter": "Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz@free.fr>",
  "eventId": "GRB 170202A"
}