[vsnet-grb-info 15024] GRB 140423A: TShAO optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16318
SUBJECT: GRB 140423A: TShAO optical observations
DATE:    14/05/22 16:23:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

A. Volnova (IKI), A.V. Kusakin (Fesenkov Astrophysical Institute)  A.V. 
Khruslov (INASAN), A. Pozanenko (IKI) report on behalf of larger GRB 
follow-up collaboration:

We observed the optical afterglow (Elenin et al., GCN 16143; Kaur et 
al., GCN 16144; Ferrante et al., GCN 16145; Chester et al., GCN 16147;
Maehara et al., GCN 16151) of the Swift GRB 140423A (Sonbas et al.,
GCN 16142) with Zeiss-1000 (East) 1m telescope of Tien Shan Astronomical 
Observatory on Apr., 23 and Apr., 24. We took several images in R-filter 
of 300 and 540 s  exposures in three epochs.

Details of the photometry are following:

date        UT start   t-T0       Filter  Exp.  OT
                       (mid, days)          (s)
2014-04-23 R 15:04:19  0.291036   R     8*300  20.47 0.14
2014-04-23 R 19:04:44  0.450758   R     6*300  20.70 0.20
2014-04-24 R 15:20:01  1.322830   R    12*540  22.17 0.10

The photometry is based on  SDSS stars, R (gri -> R transformations by 
Lupton 2005):

SDSS id                      R
J130914.51+494636.5   18.661+/-0.019
J130911.04+494854.6   20.209+/-0.053
J130924.79+494946.6   19.533+/-0.038

The light curve of the afterglow based on our previous an later 
observations (GCNs  16143, 16148, 16168, 16247, 16264) can be found in
http://grb.rssi.ru/GRB140423A/grb140423a-lc.png