{
  "bibcode": "2007GCN..6974....1B",
  "body": "E. Berger (Princeton/OCIW) and R. Covarrubias (LCO) report:\n\n\"We observed the XRT error circle of GRB 071021 (GCNs 6963,6966) in the \ni-band using the LDSS3 instrument on the Magellan/Clay telescope.  In a \ncoadded image of 1120 sec we do not detect any object within the XRT error \ncircle to a 3-sigma limit of i>23 mag.\n\nSince no z-band magnitude was reported in GCN 6972 we cannot determine \nwhether our limits are significantly deeper.  However, our non-detection \nin r- and i-band appears to indicate a redshift of z~6-6.5 (for i-band \neffective wavelength = 7600A and FWHM = 1300A).  Further observations are \nin progress.\"",
  "circularId": 6974,
  "createdOn": 1193025099000,
  "email": "eberger@astro.princeton.edu",
  "subject": "GRB 071021: Magellan i-band observation",
  "submitter": "Edo Berger at Princton U  <eberger@astro.princeton.edu>",
  "eventId": "GRB 071021"
}