{
  "bibcode": "2011GCN.11906....1K",
  "body": "D. A. Kann (TLS Tautenburg), P. Schady and J. Greiner (both MPE  \nGarching) report on behalf of the GROND team:\n\nWe observed the field of GRB 110407A (Swift trigger 450884; Wolf et  \nal., GCN #11894) simultaneously in g'r'i'z'JHK with GROND (Greiner et  \nal. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La  \nSilla Observatory (Chile).\n\nObservations started at 00:50 UT on April 8, 11 hours after the GRB  \ntrigger, and continued until ~03:30 UT. They were performed at a  \nseeing of 1.5-2.5\" and at an average airmass of 1.5.\n\nWe detect a point source within the 1.7 arcsec enhanced Swift-XRT  \nerror circle (Evans et al., GCN #11903), consistent with the optical  \nafterglow detection reported by Chuang et al. (GCN #11901) and  \nMalesani et al. (GCN #11904) in the g'r'i'z' bands. In an exposure of  \n102 mins at a mid-observing time of 02:31 UT (12.5 hours after the BAT  \ntrigger), we estimate a preliminary r'-band magnitude (in the AB  \nsystem) of 23.9+/-0.1.\n\nThe r'-band magnitude is calibrated against SDSS field stars and has  \nnot been corrected for the expected Galactic foreground extinction  \ncorresponding to a reddening of E_(B-V)=0.03 mag in the direction of  \nthe burst (Schlegel et al. 1998).",
  "circularId": 11906,
  "createdOn": 1302250239000,
  "email": "pschady@mpe.mpg.de",
  "subject": "GRB 110407A: GROND Detection of the Optical Afterglow",
  "submitter": "Patricia Schady at MPE/Swift  <pschady@mpe.mpg.de>",
  "eventId": "GRB 110407A"
}