{
  "bibcode": "2012GCN.13976....1N",
  "body": "A. Nicuesa Guelbenzu, S. Klose (both TLS Tautenburg), M. Nardini \n(Universita degli studi di Milano-Bicocca), and J.Greiner (MPE Garching) \nreport on behalf of the GROND team:\n\nWe observed the field of GRB 121117A (Swift trigger 538696, Cummings et \nal., GCN #13967) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. \n2008, PASP 120, 405) mounted at the 2.2m MPG/ESO telescope at La Silla \nObservatory (Chile).\n\nFirst-epoch observations started on November 18, 2012, at 00:16 UT, about \n15.5 hrs after the GRB trigger. Second-epoch observations were performed \nthe following night. On the first-epoch images we find a faint source \nwithin the r=1.7 arcsec XRT error circle (Beardmore et al., GCN 13972) at \ncoordinates RA(J2000) = 02:06:26.58, Dec. = 07:25:10.2 (+/- 0\".3). Within \nthe astrometric error this is consistent with the object seen by UVOT in \nthe white band during the first 200 seconds after the GRB trigger (Oates \net al., GCN 13973). For this source we measure the following preliminary \nAB magnitudes:\n\ng' > 24.0,\nr' = 23.6 +/- 0.2,\ni' = 23.0 +/- 0.2,\nz' > 23.1,\nJ > 21.3,\nH > 20.8,\nK > 19.5,\n\ncalibrated against SDSS and 2MASS field stars. On the second-epoch images \nthe object had faded to r'=24.5 +/- 0.2 and i'>24.3, implying that this \nwas the GRB afterglow.",
  "circularId": 13976,
  "createdOn": 1353364554000,
  "email": "klose@tls-tautenburg.de",
  "subject": "GRB 121117A: GROND confirmation of the UVOT afterglow candidate",
  "submitter": "Sylvio Klose at TLS Tautenburg  <klose@tls-tautenburg.de>",
  "eventId": "GRB 121117A"
}