{
  "bibcode": "2009GCN..8975....1U",
  "body": "A. C. Updike (Clemson University), C. Clemens, and J. Greiner (MPE\nGarching) report on behalf of the GROND team:\n\nWe observed the field of the possibly short/hard GRB 090309 (Swift trigger\n345945; Evans et al., GCN #8964) simultaneously in g'r'i'z'JHK with GROND\n(Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI\ntelescope at La Silla Observatory (Chile).\n\nObservations started at 07:22 UT on March 10th, 7.9 hours after the GRB\ntrigger and continued for 2.5 hours at an average seeing of 1.5\" and an\naverage airmass of 1.5.\n\nIn one hour of stacked exposures, we do not detect a source within the\nSwift-XRT enhanced error circle (Goad et al., GCN #8969) down to\n\ng' > 23.4,\n\nr' > 23.8,\n\ni' > 23.2,\n\nz' > 23.0,\n\nJ > 21.3,\n\nH > 21.0 and\n\nK > 20.3\n\nThe given limits in the AB system are derived based on calibrating the\nimages against GROND zeropoints and 2MASS field stars and are not\ncorrected for the Galactic foreground extinction corresponding to a\nreddening of E_(B-V)= 0.23 in the direction of the burst (Schlegel et al.\n1998).",
  "circularId": 8975,
  "createdOn": 1236731078000,
  "email": "aupdike@clemson.edu",
  "subject": "GRB 090309A: GROND upper limits",
  "submitter": "Adria C. Updike at Clemson U  <aupdike@clemson.edu>",
  "eventId": "GRB 090309A"
}