{
  "bibcode": "2012GCN.13579....1S",
  "body": "V. Sudilovsky, J. Elliott, and J. Greiner (all MPE Garching) report\non behalf of the GROND team:\n\nWe observed the field of GRB 120804A (Swift trigger 529686; Lien et al.,\nGCN 13573) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,\nPASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla\nObservatory (Chile).\n\nObservations started at 02:22 UT on 2012-08-04, 1.5 hrs after the GRB\ntrigger. We do not detect any sources within the XRT position reported by\nOsborne et al (GCN 13577). We do note that observations were severely\nlimited by unfavorable weather conditions, including moon-illuminated\nvisible cirrus towards the field.\n\nBased on six co-added exposures of 370s (g'r'i'z') and 240s (JHK) taken\nat a mean airmass of 1.3 and a mean seeing of 3.0\", we derive the following\nupper limits (all AB system):\n\ng' > 21.9\nr' > 22.1\ni' > 22.0\nz' > 21.9\nJ' > 20.6\nH' > 20.0\nK' > 19.5\n\nThe magnitudes are derived based on GROND zeropoints (g'r'i'z') and 2MASS\nstars (JHK). The above upper limits are not corrected for the Galactic \nextinction\nof E(B-V) = 0.23 mag along the line of sight (Schlegel et al. 1998).",
  "circularId": 13579,
  "createdOn": 1344071222000,
  "email": "vsudilov@mpe.mpg.de",
  "subject": "GRB 120804A: GROND upper limits",
  "submitter": "Vladimir Sudilovsky at MPE  <vsudilov@mpe.mpg.de>",
  "eventId": "GRB 120804A"
}