{
  "bibcode": "2008GCN..8218....1R",
  "body": "A. Rossi (Tautenburg Obs.), J. Greiner, T. Kruehler, A. Yoldas (all MPE), \nS. Klose (Tautenburg Obs.), A. Kuepcue Yoldas (ESO)\nreport on behalf of the GROND team: \n\nWe observed the field of GRB 080913 (Swift trigger 324561; Schady et\nal., GCN #8217), simultaneously in g'r'i'z'JHK with GROND (Greiner et al.\n2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla \nObservatory (Chile). Observations started at 06:50 UT on September 13, 2008, \n3 min after the GRB trigger. We detect a faint optical object inside\nthe 2.4 arcsec Swift/XRT error box (Schady et al., GCN #8217).\n\nWe detect the object only in the z'-band and NIR, but not in i'-band\nor bluer. Preliminary photometry yields the following magnitudes calibrated \nagainst USNO-B1 and 2MASS field stars in stacked images: \nr' > 23.2 mag,\ni' > 23.0 mag,\nz' = 22.4 mag,\nnot corrected for the expected Galactic foreground reddening of E(B-V) =\n0.05 mag (Schlegel et al., 1998). \n\nThe non-detection in i' and bluer may indicate a redshift of about 6.\nWe caution however, that the drop-out is only 0.6 mag in depth between\nour i' and z' bands, and our lack of better sensitivity could make this\na wrong interpretation. We encourage deeper observations.",
  "circularId": 8218,
  "createdOn": 1221296825000,
  "email": "jcg@mpe.mpg.de",
  "subject": "GRB 080913: GROND observation of a high-z optical/NIR afterglow candidate",
  "submitter": "Jochen Greiner at MPI  <jcg@mpe.mpg.de>",
  "eventId": "GRB 080913"
}