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GCN Circular 17399

GRB 150203A: ISON-NM early optical limit
2015-02-04T11:46:45Z (9 years ago)
Alexei Pozanenko at IKI, Moscow <>
L. Elenin (KIAM),  A. Volnova (IKI), E. Mazaeva (IKI),  I. Molotov  (KIAM), 
A. Pozanenko (IKI) report on behalf of larger GRB  follow-up  collaboration:

We observed the field of the Swift GRB 150203A (Ukwatta et al., GCN 17377) 
with 0.4-m telescope of ISON-NM observatory in robotic mode starting on 
Feb., 03 (UT) 04:10:19  i.e. 72 seconds after burst trigger. We obtained 60 
unfiltered images of 30 s exposure. We do not detect any source within 
enhanced XRT error circle (Evans et al., GCN 17384):

Date          UT start   t-T0             Exp.    Filter   UL (3sigma)
                               (mid.,days)    (s)
2014-02-03 04:10:19  0.00130       2*30    Clear   18.0
2014-02-03 04:10:19  0.01836     60*30    Clear   19.7

The photometry is based on nearby USNO-B1.0  stars

USNO-B1.0    RA              Dec             R2
0968-0105340 06:33:22.23 +06:53:43.2 15.41
0969-0108800 06:33:26.73 +06:56:58.4 14.77
0969-0108730 06:33:22.76 +06:55:10.3 15.73
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