{
  "bibcode": "2018GCN.23326....1S",
  "body": "P. Schady (Uni. of Bath, UK) and J. Bolmer (MPE, Garching) report:\n\n\nWe observed the field of GRB 181010A (Swift trigger 866434; Melandri et al., GCN #23309) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).\n\n\nObservations were performed in rapid response mode, and started at 05:59 UT, 3 mins after the GRB trigger. They were performed at an average seeing of 1.4\" and at an average airmass of 1.0.\n\n\nWe detect a new source at a position consistent with the X-ray and optical afterglow (Gorbovskoy et al., GCN #23310; Evans et al., GCN #23313; Emery, GCN #23317). Based on the first 3.3 min of total exposures in g'r'i'z' and 3 min in JHK, we measure the following preliminary AB magnitudes:\n\n\ng' = 20.02 +/- 0.02 mag\nr' = 19.33 +/- 0.01 mag\ni' = 19.13 +/- 0.02 mag\nz' = 18.56 +/- 0.01 mag\nJ = 17.78 +/- 0.03 mag\nH = 17.02 +/- 0.03 mag\n\n\nGiven magnitudes are calibrated against PanSTARRS and 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.03 in the direction of the burst (Schlafly & Finkbeiner 2011).\n\n\nWe thank Markus Rabus for the excellend support from La Silla.",
  "circularId": 23326,
  "createdOn": 1539273679000,
  "email": "p.schady@bath.ac.uk",
  "subject": "GROND afterglow detection of GRB 181010A",
  "submitter": "Patricia Schady at Swift  <p.schady@bath.ac.uk>",
  "eventId": "GRB 181010A"
}