[vsnet-grb-info 15801] GRB 141121A: AAO optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17089
SUBJECT: GRB 141121A: AAO optical observations
DATE:    14/11/23 13:36:48 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI), R. Inasaridze (AAO), A. Volnova (IKI), Molotov (KIAM), 
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 AS-32 
(0.7m) telescope of Abastumani Observatory. Observations were performed 
under mean seeing (FWHM) of 3.5". We obtained several unfiltered images 
on Nov. 21 starting on (UT) 20:01:35.  Within enhanced XRT position 
(Evans et al., GCN 17080) we clearly detected  afterglow of GRB 141109A 
(Tanga et al., GCN 17078; Perley et al., GCN 17081). Preliminary 
photometry is following:

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

2014-11-21 20:01:35  0.73241     clear   54*120  20.08 0.05

The photometry is based on several SDSS-DR9 stars R magnitudes 
transformed from SDSS-DR9 based on Lupton transformations:

SDSS_id                 R(Lupton)
J081028,70+221318,9     16,317
J081049,68+221012,2     17,148
J081048,76+220822,7     14,413
J081106,66+221346,9     14,626