{
  "bibcode": "2009GCN..8958....1U",
  "body": "A. C. Updike (Clemson University), C. Clemens, J. Greiner and P. Afonso (MPE \nGarching) report on behalf of the GROND team:\n\nWe observed the field of GRB 090306B (BATSS, Copete et al., GCN #8944) \nsimultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) \nmounted at the 2.2 m ESO/MPI telescope at La Silla Observatory (Chile).\n\nObservations started at 04:34 UT on March 8th, about 29.5 hours after the GRB \ntrigger, and lasted 45 min.\n\nWe do not detect a source within the Swift-XRT error circle reported by Evans \n(GCN #8947) down to (all in AB system)\n\ng' > 23.2,\nr' > 23.6,\ni' > 23.3,\nz' > 23.0,\nJ > 21.7,\nH > 21.0 and\nK > 20.1.\n\nThe given limits are derived based on calibrating the images against GROND \nzeropoints and 2MASS field stars and are not corrected for the Galactic \nforeground extinction corresponding to a reddening of E_(B-V)= 0.11 in the \ndirection of the burst (Schlegel et al. 1998).",
  "circularId": 8958,
  "createdOn": 1236605346000,
  "email": "cclemens@mpe.mpg.de",
  "subject": "GRB 090306B: GROND Upper Limits",
  "submitter": "Christian Clemens at MPE  <cclemens@mpe.mpg.de>",
  "eventId": "GRB 090306B"
}