{
  "bibcode": "2018GCN.23516....1S",
  "body": "P. Schady (Univ. of Bath) and J. Bolmer (MPE, Garching) report:\n\nWe observed the field of GRB 181203A (Swift trigger 874475; Troja et al., GCN #23493) simultaneously in\ng'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO\nLa Silla Observatory (Chile).\n\nObservations started at 02:02 UT on 4th December, 13.4 hours after the GRB trigger. They were performed\nat an average seeing of 1.6\" and at an average airmass of 1.4. \n\nWe found a faint source within the 2.0 arcsec Swift-XRT error circle reported by Goad et al. (GCN #23494) at\n\nRA (J2000.0) = 07:13:23.705\nDEC (J2000.0) = -39:48:05.29\n\nwith an uncertainty of 0.12\" in each coordinate. The source is detected in all filters apart from the z' band,\nand has a preliminary r'-band AB magnitude of \n\nr' = 23.5 +/- 0.1 mag\n\nThe above magnitude is calibrated against GROND zeropoints and is not corrected for the expected\nGalactic foreground extinction corresponding to a reddening of E_(B-V)=0.21 in the direction of the\nburst (Schlafly & Finkbeiner 2011).\n\nWe thank Angela Hempel for the excellent support from La Silla.",
  "circularId": 23516,
  "createdOn": 1544165870000,
  "email": "jan@bolmer.de",
  "subject": "GRB 181203A: GROND detection of the afterglow",
  "submitter": "Jan Bolmer at MPE/Garching  <jan@bolmer.de>",
  "eventId": "GRB 181203A"
}