[vsnet-grb-info 16283] GRB 150309A: ISON-Kislovodsk optic upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17564
SUBJECT: GRB 150309A: ISON-Kislovodsk optic upper limit
DATE:    15/03/11 12:35:27 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Vazaeva (IKI), V. Nevskiy (ISON), A. Volnova (IKI), I. Molotov 
(KIAM), A. Pozanenko (IKI),report on  behalf of larger collaboration:

We observed the field of the Swift GRB 150309A (Cummings et al., GCN 
17553) with Santel-400AN   telescope of ISON-Kislovodsk observatory 
starting on Mar. 09 (UT) 23:11:26, i.e. ~8.5 min after the burst 
trigger. In the enhanced XRT position (Osborne et al., GCN 17555) we do 
not detect any object. An upper limit is following

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

2014-09-03 23:11:26  0.02590  None     49*60    20.0

The photometry is based on USNO-B1.0 star

USNO-B1.0_id  R2

1764-0030460  15.42