{
  "bibcode": "2005GCN..4142....1C",
  "body": "B. E. Cobb and C. D. Bailyn (Yale), part of the larger SMARTS\nconsortium, report:\n\nUsing the ANDICAM instrument on the 1.3m telescope at CTIO, we\nobtained optical/IR imaging of the error region of GRB 051021\n(GCN 4116, Yoshida et al.) with a mid-exposure time of\n2005-10-22 02:53 UT, which is ~13.5 hours post-burst.\nTotal summed exposure times amounted to 36 minutes in I and 30 \nminutes in J.\n\nAt the position of the reported afterglow (GCN 4120, Fox et al.), an \nobject is marginally detected in our I-band images.  The preliminary \nmagnitude of this object is determined to be I = 22.0 +/- 0.4, in \ncomparison with several nearby USNO B1.0 stars.\n\nThe afterglow candidate is not, however, detected in the J-band.  Using \nseveral 2MASS comparison stars, the limiting magnitude of this image \nis determined to be J > 19.9 +/- 0.1.  \n\nThere is an object near to the position of the afterglow candidate \n(at RA = 1:56:35.6, Dec = 9:04:26.2) that is measured in our image\nto have a magnitude of J = 17.2 +/- 0.1.  This object is below the \ndetection limits of 2MASS, so it is not detected in the 2MASS \nimages (though it is present in the USNO B1.0 survey).  Possibly, this is \nthe object reported by Haislip et al. (GRB 4127).  Therefore, in agreement \nwith Cenko et al. (GCN 4140), there is not yet clear evidence \nto suggest that this is a high redshift event.",
  "circularId": 4142,
  "createdOn": 1130032584000,
  "email": "cobb@astro.yale.edu",
  "subject": "GRB 051021, SMARTS optical/IR observations",
  "submitter": "Bethany Cobb at Yale U  <cobb@astro.yale.edu>",
  "eventId": "GRB 051021"
}