[vsnet-grb-info 16289] GRB 150309A: AAO optic upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17570
SUBJECT: GRB 150309A: AAO optic upper limit
DATE:    15/03/12 18:16:20 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI), R. Inasaridze (AAO), Sh. Makandarashvili (AAO),   A. 
Volnova (IKI), Molotov (KIAM), A. Pozanenko (IKI) report on behalf of 
larger GRB follow-up collaboration:

We observed the field of the Swift GRB 150309A (Cummings et al., GCN 
17553)  with AS-32 (0.7m) telescope of Abastumani Observatory starting 
on Mar. 10 (UT) 01:40:54.  Within 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)

2015-03-10 01:40:54  0.12699  None     19*120   21.2

The photometry is based on USNO-B1.0 star

USNO-B1.0_id  R2

1764-0030460  15.42