{
  "bibcode": "2018GCN.22662....1S",
  "body": "The field of GRB 180418A (Swift trigger 826428; D'Elia et al., GCN #22646)\nwas observed simultaneously in g'r'i'z'JHK with GROND (Greiner et al.\n2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla\nObservatory (Chile).\n\nObservations started at 01:27 UT on 19th April, 18.7 hours after the GRB\ntrigger. They were performed at an average seeing of 1.5\" and at an\naverage airmass of 1.7.\n\nA source is detected in the g'r'i' bands at a position consistent with the\nX-ray and optical afterglow (Zheng et al., GCN #22647; Goad et al., GCN\n#22650). The source is not clearly point-like, and it is therefore\npossible that some host galaxy light is contributing to the flux. Based on\n22 min of exposure in g'r'i'z' and 20 min in JHK, the estimated AB\nmagnitudes are:\n\ng' = 23.60 +/- 0.14 mag\nr' = 23.24 +/- 0.13 mag\ni' = 22.88 +/- 0.21 mag\nz' > 22.96 mag\nJ > 21.16 mag\nH > 20.67 mag\nK > 18.82 mag\n\nGiven magnitudes are calibrated against SDSS for g'r'i'z' and 2MASS field\nstars for JHK, and they are not corrected for the expected Galactic\nforeground extinction corresponding to a reddening of E(B-V)=0.01 mag in\nthe direction of the burst (Schlafly & Finkbeiner 2011).\n\nI thank Sam Kim for his excellent support from La Silla.",
  "circularId": 22662,
  "createdOn": 1524132195000,
  "email": "pschady@mpe.mpg.de",
  "subject": "GRB 180418A GROND observations",
  "submitter": "Patricia Schady at MPE/Swift  <pschady@mpe.mpg.de>",
  "eventId": "GRB 180418A"
}