{
  "bibcode": "2009GCN.10200....1K",
  "body": "Klotz A. (CESR-OMP), Gendre B. (IASF),\nBoer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report:\n\nWe imaged the field of GRB 091127 detected by Swift\n(trigger 377179) with the TAROT robotic telescope (D=25cm)\nlocated at the European Southern Observatory,\nLa Silla observatory, Chile.\n\nThe observations started 1 hour after the GRB trigger\n(event occured during dusk). The elevation of the field\nincreased from 58 degrees above horizon and weather conditions\nwere good.\n\nWe detected the optical couterpart (OT) mentioned by\nSmith et al. 2009 (GCNC 10192). As the OT is bright,\nwe used only R filtered images. We used the reference\nstar at coordinates 02:26:15.06 -18:54:57.3 R=15.82,\n(V-R)=0.24 which is the closest star with (V-R) close\nto that of the GRB (V-R~0.1 according to GROND observations\nby Updike et al. GCNC 10195). The star at coodinates\n02:26:21.07 -18:57:18.9 R=14.02 lies at 20 arcsec of the OT.\nWe substract this star before photometry:\n\n-----------------------------------\n  Tstart    Tstop  Rmag\n  (min)     (min)\n-----------------------------------\n   69.12 - 82.19  16.4 +/- 0.2\n  106.59 - 119.67 16.7 +/- 0.3\n  144.33 - 157.41 16.7 +/- 0.3\n  182.09 - 222.83 17.0 +/- 0.2\n  229.91 - 346.22 17.1 +/- 0.2\n  367.71 - 444.61 17.4 +/- 0.2\n-----------------------------------\n\nThe decay is very low since the OT decreased\nof only 1 mag in 5 hours !",
  "circularId": 10200,
  "createdOn": 1259396559000,
  "email": "Alain.Klotz@free.fr",
  "subject": "GRB 091127: TAROT La Silla observatory optical decay",
  "submitter": "Alain Klotz at CESR-CNRS  <Alain.Klotz@free.fr>",
  "eventId": "GRB 091127"
}