{
  "bibcode": "2007GCN..6973....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 \nR-band using the LDSS3 instrument on the Magellan/Clay telescope.  In a \ncoadded image of 540 sec we do not detect any objects within the XRT error \ncircle to a 3-sigma limit of R>23.1 mag.  Further observations in R and I \nband are in progress.\"",
  "circularId": 6973,
  "createdOn": 1193020180000,
  "email": "eberger@astro.princeton.edu",
  "subject": "GRB 071021: Magellan R-band observation",
  "submitter": "Edo Berger at Princton U  <eberger@astro.princeton.edu>",
  "eventId": "GRB 071021"
}