{
  "bibcode": "2018GCN.22544....1S",
  "body": "T. Schweyer (MPE), and D. A. Kann (HETH/IAA-CSIC) report:\n\nWe observed the field of GRB 180325A (Swift trigger 817564; E. Troja et \nal., GCN #22532) 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 02:53 UTC on March 25, 1.0 hours after the GRB \ntrigger. They were performed at an average seeing of 1\".5 and at an \naverage airmass of 1.7.\n\nWe clearly detect the NIR/optical transient of GRB 180325A within the \nenhanced XRT position (J. P. Osborne et al., GCN #22539), in agreement \nwith the optical transient detected by UVOT (E. Troja et al., GCN \n#22532).\nBased on 7 minutes of exposure centered around 03:30 UTC, we measure the \nfollowing magnitudes (all in AB system).\n\ng' = 20.45 +/- 0.03 mag\nr' = 19.57 +/- 0.02 mag\ni' = 19.18 +/- 0.02 mag\nz' = 18.30 +/- 0.02 mag\nJ = 17.42 +/- 0.02 mag\nH = 16.85 +/- 0.02 mag\nK = 16.34 +/ 0.03 mag\n\nGiven magnitudes are calibrated against SDSS in g'r'i'z' and 2MASS field \nstars in JHK, and are not corrected for the Galactic foreground \nextinction corresponding to a reddening of E_(B-V)= 0.015 in the\ndirection of the burst (Schlafly & Finkbeiner 2011).\n\nWe acknowledge the excellent support from the TiO and the current \nobserver at the 2.2m in La Silla, Angela Hempel and Victor Marian.",
  "circularId": 22544,
  "createdOn": 1522000263000,
  "email": "kann@iaa.es",
  "subject": "GRB 180325A: GROND observations",
  "submitter": "Alexander Kann at IAA-CSIC  <kann@iaa.es>",
  "eventId": "GRB 180325A"
}