{
  "bibcode": "2016GCN.20113....1K",
  "body": "T. Kruehler and J. Greiner (both MPE Garching) report on behalf\nof the GROND team:\n\nWe observed the field of GRB 161023A (INTEGRAL trigger 7613;\nMereghetti et al., GCN #20103) simultaneously in g'r'i'z'JHK with\nGROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG\ntelescope at the ESO La Silla Observatory (Chile).\n\nObservations started at 23:52 UT on 2016-10-24, 25.2 hr after the GRB\ntrigger. They were performed at an average seeing of 1\".6, and at an\naverage airmass of 1.1.\n\nBased on combined images with 9.7 min of total exposures in g'r'i'z'\nand 10.0 min in JHK at a mid-time of 00:12 UT on 2016-10-25,\nwe derive the following preliminary magnitudes (all in AB system) for\nthe optical/NIR afterglow (Gorbovskoy et al. GCN 20102, Tanvir et al.,\nGCN 20104, Guidorzi et al., GCN 20107).\n\ng' = 19.7 +- 0.1 mag\nr' = 19.4 +- 0.1 mag\ni' = 19.2 +- 0.1 mag\nz' = 19.1 +- 0.1 mag\nJ = 18.7 +- 0.1 mag\nH = 18.4 +- 0.1 mag\nK = 18.2 +- 0.1 mag\n\nGiven magnitudes are calibrated against GROND zeropoints as well as\n2MASS field stars and are not corrected for the expected Galactic\nforeground extinction corresponding to a reddening of E_(B-V) = 0.03 mag\nin the direction of the burst (Schlafly & Finkbeiner 2011).",
  "circularId": 20113,
  "createdOn": 1477377458000,
  "email": "kruehler@mpe.mpg.de",
  "subject": "GRB 161023A: GROND Observations",
  "submitter": "Thomas Kruehler at MPE Garching  <kruehler@mpe.mpg.de>",
  "eventId": "GRB 161023A"
}