[vsnet-grb-info 17641] GRB 160225A: TSHAO optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19078
SUBJECT: GRB 160225A: TSHAO optical upper limit
DATE:    16/02/25 17:37:58 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI),  A. Kusakin (Fesenkov Astrophysical Institute), I. 
Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI),  A. Pozanenko 
(IKI) report on behalf of larger GRB follow-up collaboration:

We observed the Swift GRB 160225A (Siegel  et al., GCN 19075) with 
Zeiss-1000 (West) 1-m telescope of Tien Shan Astronomical Observatory. 
We obtained several images in R filter starting on  Feb. 25 (UT) 
14:46:05. In the first images we do not detect any optical source within 
enhanced Swift-XRT position (Goad et al., GCN 19077). Preliminary 
photometry of one of  single 90 s image is following


Date        UT start   t-T0    Filter  Exp.   UL (3sigma)
                       (mid, days)     (s)


2016-02-25 14:47:35   0.01903  R      1*90    18.90