{
  "bibcode": "2014GCN.16939....1K",
  "body": "D.A. Kann (TLS Tautenburg), T. Schweyer, J. F. Graham, J. Greiner \n(all MPE Garching) report on behalf of the GROND team:\n\nWe observed the field of GRB 141022A (Swift trigger 616061; Vargas et\nal., GCN #16938) simultaneously in g'r'i'z'JHK with GROND (Greiner et\nal. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La\nSilla Observatory (Chile).\n\nObservations started at 01:39 UT on October 22nd, approximately 20 min\nafter the GRB trigger. They were performed on a setting target at high\nairmass (~2.7) until reaching the pointing limit.\n\nDespite a crowed field we find only a single object in the 2.2\"\nSwift-XRT enhanced error circle reported by Vargas et al., GCN #16938) at\n\nRA (J2000.0) = 16h 07m 28.82s\nDEC (J2000.0) = -72d 07' 29.6\"  \n\n(error of 0\".5) but cannot ascertain variability in images centered \n875 sec  and 2095 sec after the trigger, and note the possibility \nof a chance coincidence given the density of objects in the field.  \nWe intended subsequent observations to determine variability.\n\nBased on a 16.5 min sequence of exposures, we estimate preliminary\nmagnitudes and limits (all in AB system) of:\n\ng' = 23.6 +/- 0.2 mag\nr' = 22.2 +/- 0.1 mag\ni' = 21.6 +/- 0.1 mag\nz' = 22.0 +/- 0.2 mag\nJ > 20.9 mag\nH > 20.3 mag\nK > 19.8 mag\n\nGiven magnitudes are calibrated against GROND zeropoints and 2MASS field\nstars and are not corrected for the expected Galactic foreground\nextinction corresponding to a reddening of E_(B-V)=0.1 mag in the\ndirection of the burst (Schlegel et al. 1998).",
  "circularId": 16939,
  "createdOn": 1413958709000,
  "email": "jcg@mpe.mpg.de",
  "subject": "GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate",
  "submitter": "Jochen Greiner at MPI  <jcg@mpe.mpg.de>",
  "eventId": "GRB 141022A"
}