{
  "bibcode": "2017GCN.21052....1K",
  "body": "Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),\nBoer, M., Laugier, R. (CNRS-ARTEMIS),\nGendre B. (UVI - Etelman Obs.) report:\n\nWe imaged the field of GRB 170428A detected by SWIFT\n(trigger 750298) with the TAROT robotic telescope (D=25cm)\nlocated at the European Southern Observatory,\nLa Silla observatory, Chile.\n\nThe observations started 25s after the GRB trigger\n(15s after the notice). The elevation of the field increased from\n18 degrees above horizon and weather conditions\nwere 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 do not detect any OT in the GROND position provided\nby Bolmer et al. (GCNC 21050) with a limiting magnitude of:\nt0+25s to t0+85s : Rlim = 17.5\n\nThe second image is 30.0s exposure in tracking mode:\nt0+98s to t0+128s : Rlim = 18.2\n\nWe co-added a series of exposures:\nt0+98s to t0+388s : Rlim = 19.2\n\nMagnitudes were estimated with the nearby NOMAD1 stars\nand are not corrected for galactic dust extinction.",
  "circularId": 21052,
  "createdOn": 1493517678000,
  "email": "Alain.Klotz@free.fr",
  "subject": "GRB 170428A: TAROT La Silla observatory optical observations",
  "submitter": "Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz@free.fr>",
  "eventId": "GRB 170428A"
}