TITLE:   GCN CIRCULAR
NUMBER:  6613
SUBJECT: GRB 070707: optical afterglow
DATE:    07/07/09 04:20:54 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

P. D'Avanzo (INAF-OABr), S. Piranomonte (INAF-OAR) & S. Vergani 
(DIAS-DCU) on behalf of the MISTICI collaboration L. Christensen,  P. 
Amico (ESO) report:

We observed again the field of the short/hard GRB 070707 (Beckmann et 
al., GCN 6605; Gotz et al., GCN 6607) with the ESO-VLT in imaging mode. 
Observations have been carried out around Jul 09.08 UT in the R band 
with the FORS1 camera.

A comparison with the images of our previous observing run (D'Avanzo et 
al., GCN 6609) revealed that the object inside the XRT error box 
(Beardmore et al., GCN 6610) reported by Piranomonte et al. (GCN 6612) 
faded of about 0.7 +/- 0.1 mag. We thus propose this object as the 
optical afterglow of GRB 070707.

Further observations are planned. We acknowledge the ESO staff for 
reliable support.

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