{
  "bibcode": "2008GCN..8540....1L",
  "body": "S. Loew, T. Kruehler and J. Greiner (all MPE Garching) report on behalf of \nthe GROND team: \n\n\nWe observed the field of GRB 081121 (Swift trigger #335105; Oates et al., \nGCN #8537) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, \nPASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla \nObservatory (Chile). \n\n\nObservations started at 00:30 UT on November 22nd, 2008, 3.9 hr after the \nburst at a high airmass of 2.35, and are continuing. \n\n\nWe detect the optical afterglow reported by Yuan et al. (GCN #8536) and \nOates & Schady (GCN #8538) clearly in all filters. \n\n\nAt a midtime of 3.9454 hours after the burst, we estimate the following \npreliminary magnitudes (all in AB system) in stacked images of 4 x 35s \nintegration in g'r'i'z' and 24 x 10s integration in JHK: \n\n\ng' = 19.1\nr' = 18.8\ni' = 18.6\nz' = 18.5\nJ = 18.4\nH = 18.2\nK = 18.1 \n\n\nwith typical errors of 0.2 mag, which are mostly due to a preliminary \ncalibration using GROND zeropoints in g'r'i'z' and 2MASS field stars in JHK.",
  "circularId": 8540,
  "createdOn": 1227322934000,
  "email": "sloew@mpe.mpg.de",
  "subject": "GRB 081121: GROND observations",
  "submitter": "Sebastian Loew at MPE  <sloew@mpe.mpg.de>",
  "eventId": "GRB 081121"
}