GCN Circular 22315
Subject
GRB 180103A: LCO Sutherland 1-m telescope observations
Date
2018-01-10T18:59:27Z (6 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU) on behalf of a large collaboration report:
We observed the field of Swift GRB180103A (Beardmore et al. GCN 22305) on January 06, from 22:12 to 22:35 UT (3.9 days post burst) with one of the 1-m LCO telescopes in Sutherland in the SDSS-I filter. Within the XRT error circle of the source mentioned by Melandri et al. (GCN 22308) we see two sources, for which we measure the following magnitudes:
RA(J2000.0) DEC(J2000.0) Exposure Filter Magnitude (AB)
(s)
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10:38:24.24 -53:33:17.3 9x120 SDSS-I 19.68 +- 0.07
10:38:24.64 -53:33:21.3 9x120 SDSS-I 19.19 +- 0.05
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as calibrated against USNO UCAC4 field stars. Although we presently cannot make any statement about possible variability, the crowded field suggests that both sources are likely to be unrelated to the GRB. No other sources down to i<20.8 mag are seen within the same XRT error circle.