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GCN Circular 6974

GRB 071021: Magellan i-band observation
2007-10-22T03:51:39Z (17 years ago)
Edo Berger at Princton U <>
E. Berger (Princeton/OCIW) and R. Covarrubias (LCO) report:

"We observed the XRT error circle of GRB 071021 (GCNs 6963,6966) in the 
i-band using the LDSS3 instrument on the Magellan/Clay telescope.  In a 
coadded image of 1120 sec we do not detect any object within the XRT error 
circle to a 3-sigma limit of i>23 mag.

Since no z-band magnitude was reported in GCN 6972 we cannot determine 
whether our limits are significantly deeper.  However, our non-detection 
in r- and i-band appears to indicate a redshift of z~6-6.5 (for i-band 
effective wavelength = 7600A and FWHM = 1300A).  Further observations are 
in progress."
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