{
  "bibcode": "2008GCN..8510....1C",
  "body": "C. Clemens, T. Kruehler, J. Greiner (all MPE Garching) and G. Szokoly \n(Eoetvoes Univ., Budapest and MPE) report on behalf of the GROND team:\n\nWe observed the field of GRB 081109 (Swift trigger #334112; Immler et al., GCN \n#8500) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP \n120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla Observatory \n(Chile).\n \nObservations started at 00:08 UT on November 10th, 2008, 17.1 hr after the GRB \ntrigger, and are continuing. They were performed during astronomical twilight \nat an average seeing of 1.0\" and at an average airmass of 1.1 as well as \nunder bright Moon.\n \nBased on the first 7.7 min of total exposures in g'r'i'z' and 8.0 min in JHK, \nwe detect the afterglow candidate reported by D'Avanzo et al. (GCN #8501) and \nestimate preliminary magnitudes (all in AB system) of\n \ng' > 22.8\nr' ~ 22.8 +/- 0.3\ni' ~ 21.8 +/- 0.15\nz' ~ 21.4 +/- 0.15\nJ ~ 20.4 +/- 0.10\nH ~ 19.7 +/- 0.15\nK ~ 18.9 +/- 0.20\n \nThese magnitudes are calibrated against GROND zeropoints as well as \n2MASS field stars.\n \nThe spectral energy distribution is very red, and requires an extinction\nof A_V > 0.5. With this strong extinction, and our g'-band limit being\ncompromised by the nearby full Moon, we cannot derive a redshift\nat this stage.",
  "circularId": 8510,
  "createdOn": 1226288092000,
  "email": "cclemens@mpe.mpg.de",
  "subject": "GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate",
  "submitter": "Christian Clemens at MPE  <cclemens@mpe.mpg.de>",
  "eventId": "GRB 081109"
}