GCN Circular 6967
T. Sakamoto (GSFC/UMBC), N. Gehrels (GSFC) and Kim Page (U. Leicester) We point out that GRB 071021 has several signatures of high redshift. As pointed out in GCN 6966, it has BAT high-redshift indicators (Sakamoto et al. 2007 in prep.) as follows: - long duration T90 = 225 sec - relatively few (two) significant peaks - peak flux (1 s) < 1.0 ph/cm2/s - power-law photon index (1.70) < 2 Since May 2007, only this burst and GRB 071018 (GCN 6933) have satisfied all four indicators. GRB 071021 also has an X-ray afterglow lightcurve with strong late-time flares (GCN 6963; see http://gcn.gsfc.nasa.gov/gcn/other/071021_xrtlc.gif) reminiscent of high-redshift burst GRB 050904. It also has optical observations without detection (GCN 6961, 6962). Deep IR observations are strongly encouraged.