GCN Circular 21375
Subject
GRB 170728B: LT afterglow confirmation
Date
2017-07-29T04:50:11Z (7 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath), A. Gomboc (U. Nova
Gorica), S. Kobayashi, I.A. Steele (LJMU) on behalf of a large
collaboration report:
We began observing Swift GRB 170728B (Cenko et al. GCN 21371) on July
28, 23:06:47 UT (208 seconds since the GRB trigger) with 2-m Liverpool
Telescope with RINGO3 polarimeter and IO:O camera in the SDSS R filter.
We clearly detect the optical counterpart (D'Avanzo et al. GCN 21373;
Heintz et al. GCN 21374) with r'=20.43 +- 0.12 mag in a 6x10s frame at a
mid time of 36.5 minutes since GRB, as calibrated against nearby
Pan-STARRS1 sources.