TITLE:   GCN CIRCULAR
NUMBER:  17102
SUBJECT: GRB 141121A: Continued Mondy optical observations
DATE:    14/11/26 22:52:46 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), M. Eselevich 
(ISTP), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger 
GRB follow-up collaboration:

We observed the field of GRB 141121A (Lien et al., GCN 17075) with 
AZT-33IK telescope of Sayan observatory (Mondy) on Nov., 26  starting on 
(UT) 20:16:58.  We obtained several  images in R-filter. In a combined 
image we clearly  detect optical  afterglow (Tanga et al., GCN 17078; 
Perley et al., GCN 17081).

A preliminary photometry is based on nearby SDSS  stars:

date       UT start   t-T0     Filter   Exp.    OT    OT_err
                               (mid, days)       (s)

2014-11-26 20:16:58   5.7120   R        39*120  21.38 0.09

The magnitude of the afterglow decreased about 0.9 mag since our 
previous observation (Mazaeva et al., GCN 17093) at 2.74 days after the 
burst trigger and thus we confirm gradual steepening of the afterglow 
light curve (Butler et al., GCN 17101).