TITLE:   GCN CIRCULAR
NUMBER:  20448
SUBJECT: GRB 170113A: LCO Sutherland observations
DATE:    17/01/13 12:18:14 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), A. Gomboc 
(U. Nova Gorica), C.G. Mundell (U. Bath) on behalf of a large 
collaboration report:

We observed Swift GRB 170113A (Evans et al. GCN 20446) on January 13, 
from 10:53:32 UT (50 minutes since the GRB) with 1-m LCO telescope units 
in Sutherland with SDSS r and i filters. We clearly detect the 
Swift-UVOT optical counterpart with the following values:

Mid Time      Exposure       Filter       Magnitude (AB)
(hours)           (s)
-------------------------------------------------------
0.89             5x60         SDSS-R      19.06 +- 0.11
0.89             5x60         SDSS-I      18.84 +- 0.08
-------------------------------------------------------

as calibrated against nearby USNO-UCAC4 sources.