TITLE:   GCN CIRCULAR
NUMBER:  13856
SUBJECT: GRB 121011A: NOT optical observations
DATE:    12/10/11 22:54:21 GMT
FROM:    Dong Xu at Weizmann Inst  <dong.dark@gmail.com>

J. P. U. Fynbo (DARK), D. Xu (WIS), D. Malesani (DARK), A.
Sodor(Konkoly Observatory of Hungary, Royal Observatory of Belgium) ,
P. Jakobsson (U. Iceland) report on behalf of a larger collaboration:

We observed the optical afterglow of GRB 121011A (Racusin et al.,
GCN13845) using the 2.5m Nordic Optical Telescope (NOT) equipped with
ALFOSC.

The afterglow is clearly detected in each of the two 300s exposures,
with a mean time Oct. 11.830 UT (i.e., 8.666 hr after the BAT
trigger). We found its magnitude R=21.76+/-0.10, calibrated with the
USNO B1 star # 1310-0279773 (R1 = 17.84; same as calibration in
Malesani et al., GCN #13853).

We also carried out 2x20 min spectroscopic observations after the
above photometry. There is a faint trace in the 2D spectrum but the
S/N in the 1D spectrum is low. Preliminary analysis of the 1D spectrum
shows very weak sign of z~0.58.