[vsnet-grb-info 5283] GRB 071021: Magellan i-band observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6974
SUBJECT: GRB 071021: Magellan i-band observation
DATE:    07/10/22 03:51:39 GMT
FROM:    Edo Berger at Princton U  <eberger at astro.princeton.edu>

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."