{
  "bibcode": "2012GCN.13827....1R",
  "body": "A. Rossi (TLS Tautenburg), P. Schady and  J. Greiner (MPE Garching)  \nreport on behalf of the GROND team:\n\nWe observed the field of GRB 120927A (Swift trigger 534815; Maselli et  \nal., GCN 13822) simultaneously in g'r'i'z'JHK with GROND (Greiner et  \nal. 2008, PASP 120, 405) mounted at the 2.2m MPG/ESO telescope at La  \nSilla Observatory (Chile).\n\nObservations started at  09:05 UT on Sep 28, 10.4 hrs after the GRB  \ntrigger, as soon the target became visible from La Silla. They were  \nperformed at an average seeing of 2.6 arcsec and at an average airmass  \nof 2.3. It was only possible to observe for a total exposure time of  \n7.2 min in the g'r'i'z' bands during morning twilight, whereas in the  \nJHK bands we were able to observe for a total of 32 min.\n\nUsing our full data set, we do not detect any source within the  \nrefined XRT error circle (Beardmore et al., GCN 13824) in our stacked  \nGROND images down to the following 3 sigma limiting magnitudes (AB)  \nmags:\n\ng' > 22.4\nr' > 22.5\ni' > 21.9\nz' > 21.9\nJ  > 21.3\nH  > 21.0\nK  > 19.4\n\nThe g'r'i'z and JHK bands are calibrated against SDSS and 2MASS,  \nrespectively, and the above limits are not corrected for the Galactic  \nforeground reddening of E_(B-V)= 0.04 mag in the direction of the  \nburst (Schlegel et al. 1998).\n\nWe note the presence of a source south of the enhanced XRT position,  \nwhich is already present in DSS2 images.",
  "circularId": 13827,
  "createdOn": 1348844273000,
  "email": "pschady@mpe.mpg.de",
  "subject": "GRB 120927A: GROND upper limits",
  "submitter": "Patricia Schady at MPE/Swift  <pschady@mpe.mpg.de>",
  "eventId": "GRB 120927A"
}