{
  "bibcode": "2016GCN.20132....1G",
  "body": "A. Nicuesa Guelbenzu, S. Schmidl (both TLS Tautenburg) and J. Greiner\n(MPE Garching) report on behalf of the GROND team:\n\nWe observed the field of GRB 161104A (Swift trigger 720568; Mingo et\nal., GCN 20123) simultaneously in g'r'i'z'JHK with GROND (Greiner et\nal. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the ESO\nLa Silla Observatory (Chile).\n\nObservations started at 04:00 UT on 2016-11-05, 18 hours after the GRB\ntrigger. They were performed at an average seeing of 1\" and at an\naverage airmass of 1.2.  Inside the enhanced 3.2\" XRT position (GCN\n20124, Goad et al.) we find a single source at coordinates:\n\nSource A\nRA (J2000.0) = 05:11:34.46\nDEC (J2000.0) = -51:27:36.3\nwith an uncertainty of 0.5\" in each coordinate.\n\nAt the border of the XRT error circle lie two more sources  at coordinates:\n\nSource B\nRA (J2000.0) = 05:11:34.31\nDEC (J2000.0) = -51:27:33.6\n\nSource C\nRA (J2000.0) = 05:11:34.73\nDEC (J2000.0) = -51:27:34.2\n\nTheir r'-band AB magnitudes are:\n\nSource A\nr' = 24.1 +- 0.1 mag,\nSource B\nr' = 24.3 +- 0.1 mag,\nSource C\nr' = 25.1 +- 0.3 mag,\n\nFor the moment no evidence for a fading of any of these objects can be\nstated.\n\nGiven magnitudes are calibrated against GROND zeropoints and are not\ncorrected for the Galactic foreground extinction corresponding to a\nreddening of E_(B-V) = 0.01 mag in the direction of the burst\n(Schlafly & Finkbeiner 2011).\n\nWe thank Angela Hempel, La Silla, for performing the observations.",
  "circularId": 20132,
  "createdOn": 1478331441000,
  "email": "ana@tls-tautenburg.de",
  "subject": "GRB 161104A: GROND observations",
  "submitter": "Ana Nicuesa at TLS Tautenburg  <ana@tls-tautenburg.de>",
  "eventId": "GRB 161104A"
}