{
  "bibcode": "2010GCN.10835....1N",
  "body": "A. Nicuesa (TLS Tautenburg), T. Kruehler and J. Greiner (MPE\nGarching) report on behalf of the GROND team:\n\nWe observed the field of GRB 100606A (Oates et al., GCN 10824)\nsimultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP\n120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla\nObservatory (Chile).\n\nObservations started at 04:27 UT on June 07, 9.2 hours after the\nGRB trigger.\n\nWithin the enhanced XRT error circle (Evans et al. GCN 10827)\nwe confirm the presence of the blue and extended source reported by\nLevan et al. (GCN 10831) in g' and r' at\n\nRA (J2000.0) = 23:22:30.27\nDec (J2000.0) = -66:14:27.1\n\nwith typical uncertainties of 0.5\" in each coordinate.\n\nSimilar to Levan et al. (GCN 10831) we also do not find evidence of an \noptical/NIR afterglow.\n\nStacked images of 270 min total integration time in g'r'i'z' and\n80 min in JHK yield the following preliminary upper limits\nin the AB system, which have been obtained using the GROND zeropoints\nand 2MASS field stars as reference:\n\ng' > 25.7 (24.7 +- 0.2)\nr' > 25.5 (25.0 +- 0.3)\ni' > 24.6\nz' > 24.1\nJ  > 22.2\nH  > 21.5\nK  > 21.0\n\nMagnitudes in brackets denote the brightness of the putative host galaxy.\n\nUsing the r'-band upper limit and the X-ray brightness at a similar \ntime, beta_oX is constrained to be smaller than 0.6, implying that the \nburst would not be necessarily 'dark' according to the Jakobsson et al. \n(2004, ApJ, 617, 21) classification. Thus, our limit neither implies \nlarge redshift nor large extinction.",
  "circularId": 10835,
  "createdOn": 1276085727000,
  "email": "kruehler@mpe.mpg.de",
  "subject": "GRB 100606A: GROND observations",
  "submitter": "Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>",
  "eventId": "GRB 100606A"
}